Phantasy Star IV: The End of the Milennium is a direct sequel to the second Phantasy Star game, returning to the Algol System a thousand years after the events of Phantasy Star II. The game stars Chaz Ashley, an apprentice Bounty Hunter who lives and trains on Motavia with his partner and mentor Alys Brangwyn. Chaz and Alys are summoned to the Motavia Academy, where they're hired to deal with an unfortunate monster infestation of the school's basement, then to investigate the cult that is causing suffering and destruction all over the planet. This eventually leads Chaz on a mission across the entire system, where he finally discovers the truth behind Dark Force.Generally considered to be the apex of the original tetralogy for a number of reasons (not the least of which was the more advanced technology behind the game allowing for a much more expansive and better-produced experience than its predecessors), and more arguably the best game of the entire franchise. Certainly it's one of the highest-reviewed entries and holds a special place in the hearts of longtime fans.The tech for the game did require a very expensive cart. The game was first sold at double the average for games at the time. Fortunately, the game has since been released on several compilations, and is available on the Virtual Console, each at a fraction of that price.
Provides Examples Of:
Abusive Precursors: The advanced, space-faring civilisation of the first two games was reduced to Precursor status by the cataclysmic ending of Phantasy Star II. By the time of Phantasy Star IV, all the bio plants and climate-control facilities they left behind have gone haywire and started producing hordes upon hordes of monsters and causing earthquakes and environmental degradation. This was the best they could do, however; the facilities were originally created by invaders from Earth to subvert, weaken, and ultimately destroy Algol's civilization, who are the true Abusive Precursors.
Arbitrary Headcount Limit: Justified; if a character isn't on the battlefield, they're not in your party, because the plot makes sure that whenever someone leaves, there's someone new to take up the fifth slot, right up until the end: there's only five Rings of the Stars, so you'll have to choose your fifth member. It's arbitrary because no one can equip the Rykros Ring, so whoever you pick at the end doesn't get one anyway.
Awesome but Impractical: While most of the game's combination techniques are Awesome yet Practical, the ultimate one isn't really any use at all, because it bumps into the game's (fairly low) damage limit and does less damage than your late-game characters can do individually.
Awesome yet Practical: The various instant-kills of the game never work on bosses, and the vast majority only work on certain (very large) subsets of enemies. Within these limits, they work surprisingly often, and as most have their own quantity of uses, employing them generally doesn't limit a character's ability to do anything else. So, during long dungeon crawls, instant-kill attacks are an effective way to preserve a party's strength for the boss.
Special mention goes to the Vol and Savol techniques. Not very many games even have an instant-death attack with a 90% success rate.
Many Combination Attacks are also this, as they're generally less-expensive ways to wipe out random encounters and/or do large amounts of damage to bosses.
Batman Can Breathe in Space: Averted and played straight. When first arriving at the Air Castle, which is floating amidst the asteroid field of debris that is the remains of the planet Parma, the party is genuinely surprised to find a breathable atmosphere waiting for them. However, on the artificial satellites Kuran and Zelan, there are a number of places traversed by Chaz and Co. that look directly upon the vacuum of space and aren't visibly enclosed in any meaningful way.
They're big ass windows. If you look at the shape of the satellites themselves, they both have a huge-ass bridge connecting the two wings of the structure, probably to contain spaceships. The party is just walking through the enclosure.
Batman Gambit: A client in one of the guild missions tries to pull one off by siccing some hired hunters onto the head honcho of a flock of birds he himself bred. He assumed the hunters would be defeated and his fellow villagers would be encouraged to leave the flock alone. It backfires on him, since the hunters he hired just got back from fighting an Eldritch Abomination.
Incidentally, his choice of words ("head honcho bird") was mercilessly lampooned in the Let's Play run of PSIV.
Beyond the Impossible: Wren and Demi are androids, hundreds of years old, and have no biological components but if you get their levels high enough, they will eventually gain points in the Mental stat (they normally have 0, because they're machines), and although they never learn anything to spend them on, they will gain Technique Points.
Bishonen Line: Dark Force fight one is against an organic blob monstrosity (with a face) integrated into a wall of machinery, fight two is against a chitin-armored juggernaut scorpion thing covered with fang-filled maws that also has (the same) face, and fight three is against a giant nightmare humanoid with a sword for an arm.
The Profound Darkness would be a more traditional example, as its first and second forms are gigantic and even more nightmarish versions of the first two fights mentioned above, and its final form is a still-colossal, apparently female, and rather nubile humanoid with long, glowing tresses.
Bittersweet Ending: The Profound Darkness is defeated once and for all, but the heroes all return to where they come from. And since Wren and Demi take the Landale to Zelan with them, Chaz has absolutely no chance of ever seeing Raja or Kyra again. Basically the implication is that everyone returns to their lives and none of them ever see each other again.
It's worse than that. The environmental control systems that have kept Algol habitable until now are working again, with both proper androids in control... but they're deteriorating, and will eventually fail completely; fanfics have been written about what that means for the Parmanians, who have no native climate to return to once the natural environments of Dezolis and Motavia reassert themselves.
This isn't true. Both Wren and Demi implicitly state that the weather control systems have stabilized. Motavia will never be as terraformed as it'd been in Phatansy Star II, but it's not going to get any worse. Both Androids remain at Zelan to monitor the systems and make sure they remain stable. The fact that they tell Chaz that one day they will no longer be necessary to the system indicates that the system will be fine on its own, and the Parmanians don't have to worry about becoming extinct.
That depends on how you read it. Wren and Demi are necessary as long as the system exists, but the system is already irrevocably damaged, it's only stabilized at the level of damage it's already taken. Considering the changes from PSII to PSIV, the system wasn't capable of keeping Motavia hospitable forever even at its best; once it finally collapses after Wren and Demi help it limp along for as long as possible, they won't be necessary.
Blunt Metaphors Trauma: Alys is referred to as "Alys the Eight Stroke Sword", and takes great offense to it, leading to some players wondering why she would be so bothered by such a cool nickname; the phrase in Japanese is a little closer to "Rip-Their-Guts-Out Lyla", which is a bit more understandable. This still makes sense in either translation when you realize she's a consummate professional who makes it obvious she doesn't like to brag.
Early in the game, Infantworms would burrow under the ground and either call mommy or grow up really, really fast, as you'd find yourself facing a Sand Worm that you were most likely ill-equipped to fight at that point. This occurs after an optional mission involving a sand worm fight, and so the player may expect the battle to go at least similarly or, more likely, with greater ease. Turns out it doesn't quite happen that way.
(Much) later on, you'd encounter the Prophallus, and boy, was he a hard one. Who knew that a monster with only one attack could mop the floor with your Ragtag Bunch of Misfits so effortlessly? Then again, with a name like his, he must have had the living falz teased out of him on the demon playground as a kid. All that resentment's gotta go somewhere.
Broken Bridge: Quite a few, though generally not solved with "fixing the bridge." The more common solution is "now we've got a super-high-tech vehicle that obviates the obstruction."
The one absolutely straight example is the bridge that connects the two landmasses between Zema and Nalya. You can't cross until after Rika joins your party.
Bruiser with a Soft Center: When Alys isn't busy maintaining her status as the guild's top hunter, pressuring information out of suspicious clients, slugging dirty old men in the face and being all around badass, she cooks tasty food for her elderly neighbour... which genuinely surprises the other party members when it's revealed. Much to Alys' embarassment. Said neighbour later reveals Alys is also into poetry. You do the math.
But Now I Must Go: Everyone leaves to return to their lives at the game's end. But this applies to Rune more than the others, as he as to pass on Lutz' essence to future generations.
Call a Rabbit a "Smeerp" / Call a Hit Point a "Smeerp": Each character has two pools of abilities, called "Techniques" and "Skills." Using Techniques draw from a character's pool of Technique Points and generally look and act like magic spells. Skills generally involve some kind of physical act or special talent and follow a Fire-And-Forget model that allows each individual learned Skill to be used a certain number of times. Both Technique Points and Skill uses are restored during rests. This distinction wouldn't merit a mention were magic not an in-universe phenomenon declared to be separate from Techniques; the magic abilities certain party members learn are Skills, not Techniques.
Combination Attack: Certain combinations of techniques and/or skills will result in these as long as nobody else acts in between the involved characters' turns. Results in a
Disc One Nuke: By the time the first dungeon is finished you should have access to Triblaster Foi + Wat + Tsu. It can oneshot anything you encounter in random battles and is potent enough to be of use in boss fights for nearly the entirety of the time you spend on Motavia.
The game also has a few enemies that can either combine to become a bigger, meaner monster or team up to unleash a very painful attack on your entire party. You want to let the former happen since the bigger monster gives more experience, but the latter is to be avoided at all costs. One trio of bosses also uses a painful combination attack as a counter against multitarget attacks.
Continuity Nod: One of the towns contains a statue of Alis Landale, heroine of the first game. A store in that same town even sells expensive souvenirs, including "Alis' Sword", a pathetic (toy) weapon with really low attack power.
Cosmic Horror Story: This game reveals that the Algo System is the padlock on a dimensional cage sealing the Profound Darkness. Palmans, Motavians, and Dezorians were created by the Great Light to prevent the Profound Darkness from breaking free—and that the reign of Lassic and the destruction of Palma by the Earthlings were just a part of its attempts to escape. Chaz is not happy with this, though he ultimately stands against the Darkness anyway.
Crutch Character: Alys is much more powerful than the other early game characters at first, but even leaving aside the fact that you lose her after her Plotline Death, her growth curve is such that other characters quickly catch up if you level grind.
Not to mention Rune, when he first joints the party; he's capable of wiping out screenfuls of enemies with a single attack and comes with a weapon that can be used as an unlimited supply of healing spells. Taking a moment to level grind with a macro that starts with someone using the Wood-Cane and Rune casting Hewn or Gra is a very easy exploit.
Cutscene Power to the Max: Rune's Flaeli skill is only a bit stronger than his weakest fire spell, but in a cutscene he can blast a wall of rocks to dust with it.
Deadpan Snarker: Raja first and foremost, but Alys and Rune also have their moments.
Decoy Protagonist: Alys. Considering how similar her name is to the protagonist of the first game, you'd think she was the main character, wouldn't you? Beside, she's usually swapped into the first character slot when she joins and acts like a leader.
Foreshadowing: The first time the player has control of the party, it's Chaz by himself.
The Dev Team Thinks of Everything: If you want to find out if the dialogue changes if you don't have anyone who can cast Gires when Alys dies, you will find that Juza will spam his powerful Forceflash ability (unless one of your your healers will level up and master Gires with the EXP gained from defeating him) to kill your entire party. Even if you grind to make Alys and Gryz as powerful as possible, Gryz's lack of useful Skills and Techniques and Alys' extremely slow and limited growth path, as well as the fact that neither of them have healing techniques, mean that Juza will still wipe the floor with them. It'll just take longer.
Guards don't let you leave first city until you've done with the story. You can try spending several hours grinding monsters in very first dungeon in horribly painful attempt to gain access to level 7 and spell that would teleport you to world map, but even then guards would appear on world map along you and drag you back.
Disc One Final Dungeon: Nurvus, especially since all of the plot development up to that point indicates the problems will be solved once through. Veterans of the series would understand that the lack of space travel would indicate the game isn't over, leading to the second Disc One Final Dungeon at the Kuran satellite. After vanquishing Dark Force and restoring order to Algol's rogue climate-control systems, it might almost seem like the game was over. Nope.
....and then they do it again with Garuberk Tower.
Does This Remind You of Anything?: Demi asks for everyone else to turn their back to her and close their eyes while she installs a new weapons system. Chaz lampshades this with his confusion at the request.
It must be stated that this secret weapon just so happens to be installed in her chest of all places, oddly enough.
Probably The Great Light as well, but we never see... When Le Roof gives his history lesson, at one point all we see are cosmic images like galaxies supposedly representing them.
Elemental Rock-Paper-Scissors: PSIV has some fairly standard ones like fire, ice, lightning and light elements, but it also has more obscure categories like "force" (most physicals and wind), energy, holy (different from light), EMP and "destruct".
Enemy to All Living Things: The Profound Darkness, given that even limited exposure to its power is enough to cause everything in the vicinity to die.
Expy: Rune (Lutz of Phantasy Star), Rika (Nei of Phantasy Star II), and Wren (Wren of Phantasy Star III) are all very similar to major characters from previous games in the franchise.
Rika was initially meant to be Nei herself by one of the designers, but his colleagues made him change her into a new character.
Justified in Rune's case because Lutz has been passing on his essence to successors since his body's physical death in anticipation of future generation's need to fight against Dark Force.
And justified in Wren's case because they're both robots of similar models. The "Wren" model series can be found as random encounters in most of the technological facilities; the Wren who joins your party just happens to be the top bot in the AI hierarchy.
AND justified in Rika's case. Nei (well, Neifirst, anyway) was initially an experiment by the Motavian bio systems in genetic engineering, and Rika was created by SEED (who happens to be the Motavian bio system) based on roughly a thousand years' worth of research into genetic engineering. If Neifirst was the Flawed Prototype, Rika would be the Super Prototype made at a much later time. SEED doesn't get around to making a production model.
Fantastic Racism: Strongly implied to be the reason Zio wiped out a village of native Motavians, though the implied in game reason was they had the only known cure for Zio's stone curse.
Foreshadowing: The first time the player has control of a character, it's Chaz...after being separated from Alys. She's a Decoy Protagonist, and Chaz becomes the party leader proper after she dies.
Game-Breaking Bug: The game would screw up a character's stats if they reached level 99.
Good Bad Translation: Some links between this title and previous games, along with a few Mythology Gags, are lost in the western version due to Dub Name Changes, plot rewrites, etc, such as when Daughter is moaning at "For...n..." (Fuoren, Wren in the US version) when she is defeated.
Good Is Not Nice: The Great Light and its followers aren't evil, but they're not nice either. While they're supportive to Chaz and company, and aid them with the necessary equipment to stand against the Profound Darkness, they also require that Chaz's group go through tests of physical and magical combat to prove themselves. Le Roof, at least, seems to be genuinely affectionate.
Re-Faze, of all the guardians of Rykros, is the most literal example of a Jerk with a Heart of Gold. Just as long as you say no to his offer.
Guide Dang It: Figuring out the fourteen Combination Attacks is a matter of trial and error, one of which (Lethal Image) can be used for only a very short time. Many players will likely never realize that they've missed it. Also, the combinations of Blizzard, Conduct Thunder, Fire Storm and Shooting Star get much stronger if you use higher-level spells (NaWat instead of Wat, etc...) as opposed to lower ones.
Several of the weapons in the game can be used as items to create magic effect, especially staffs. Rune's initial weapon, the wood-cane, can be used to produce a Res effect that will pull its weight for the whole first quarter of the game.
Heroic BSOD: Chaz has several over the course of the game, with the first coming right after the death of Alys.
Heroic Sacrifice: Alys saves Chaz' life by leaping in front of an attack intended for him.
Hijacked by Ganon: Subverted. At first the new character Zio is set up as the villain, but then it turns out he's a servant of Dark Force, the perennial Phantasy Star Final Boss. Then you beat Dark Force midway through the game, and the actual final boss is the creature that keeps bringing Dark Force back, The Profound Darkness.
History Repeats: The opening sequence involving the investigation of Motavia Academy is actually older than you might suspect; a very similar event happened in Phantasy Star II Text Adventures, with Hugh Thompson as a student of Motavia University investigating a biomonster infestation at the behest of the principal.
In fact, the monster Hugh had to take care of WAS an Igglanova (the boss critter in PS 4's basement) during the earlier stages of its evolutionary development.
Re-Faze. Though in this case it is not part of the storyline, but a result of choosing poorly to its offer. You are still taught Megid in a sense... by having it used on you to your death. Without cheating, it is impossible to win because Re-Faze has more HP than any other enemy in the game, is faster than Chaz, and does nothing but spam Megid endlessly.
Humanoid Abomination: Many basic enemies are (sometimes very visibly) organic nightmare humanoids, with the "Dark"-esque ones being almost entirely so. Dark Force number three also qualifies.
Kleptomaniac Hero: Averted / Lampshaded; if you attempt to steal from peoples' houses, Chaz will remark that "it's not very nice to look through other peoples' cabinets without their permission" - the only exception is the cabinet in his own room, which contains only underwear.
Leaning on the Fourth Wall: Rune's farewell address in Tonoe. Rune tells Chaz not to get any silly ideas in his head, such as taking on Zio. "At this stage of the game, you're no match for him!"
Level Grinding: Defied. If you reach the level cap, you actually start losing points in your stats — Word of God is that this was intentional, to prevent gamers from simply powergaming their way to victory.
Linear Warriors, Quadratic Wizards: Subverted; when he first joins your party, Rune is of a much higher level than the other party members and can pretty much tear through any mooks you encounter on his lonesome. When he later re-joins the party, they've caught up, and while he remains powerful until the end of the game, he's not noticeably moreso than the other characters.
Long Song, Short Scene: "Take Off! LANDEEL" is a peppy synth-poppy tune that takes about fifty seconds to play all the way through and perhaps thirty seconds to hear everything the song has to offer. It only plays during space-travel cutscenes that, at their longest, last twenty seconds. The times when the cutscenes are longer, the song switches to some different cutscene BGM.
Lost Forever: Make sure you do the last Hunter's Guild mission before making your second visit to Esper Mansion and getting Elsydeon. If you don't, you'll be barred from Vahal Fortress, preventing the acquisition of Wren's most powerful gun and skill.
Magic Knight: Chaz eventually evolves into one; Kyra can be one too.
The Mole: Seth. You know who else liked to use Deathspell and Corrosion a lot? That's right, Dark Force.
According to some fans, Seth may not have known about his Dark Force lineage, and went about life as an ordinary man before his true nature was revealed—or he may even have been the victim of Demonic Possession.
Mook Maker: Igglanova and Guilgenova. Nurvus and Kuran also contain some droids that can summon reinforcements and then use them to blow your party away with a Combination Attack.
No Endor Holocaust: The setting is premised on an aversion. T destruction of the planet Parma as well and the sudden terminal shutdown of the central control systems of Algol's environment-controlling machinery lead directly to the fall of their space-faring civilization as well as the deaths of 90% of the system's inhabitants, and the game picks up a thousand years later.
The Air Castle starts to fall apart once Lashiec is defeated. Understandable since the conditions that enabled the Air Castle to exist, floating alone in an asteroid belt with a breathable atmosphere and Earthlike gravity, were in pretty harsh contravention to the laws of physics.
Oh Crap: There are two closeups of Chaz in the game where his face says exactly this. The first one is when Zio launches a Death Ray (literally) right at him. The second one is played for laughs as the group's shuttle is about to crash, but for some reason only Chaz is thoroughly freaking out over it.
Precision F-Strike: Had some profanity, but at appropriate moments, and done rather tastefully. One of the villians even lampshades it.
Precision-Guided Boomerang: Alys and Kyra are wicked accurate with boomerangs and slicers. They do miss from time to time (Kyra more often than Alys) but it's seldom and the weapon type has the benefit of targeting all present enemies with every attack. You're almost guaranteed to hit at least one of your targets and in those cases where there's a single target and every hit counts (e.g. boss battles), they're going to be using other tactics anyway.
Red Baron: Alys the Eight Stroke Sword, or for an alternate translation, Rip-Their-Guts-Out Lyla.
Red Oni, Blue Oni: After Rune sheds his Jerkass facade and rejoins the group, he and Chaz become this, with Chaz as red and Rune as blue. (even reflected by the color of their clothes) This principle also holds true for the main group as a whole, with Chaz and Rika forming the heart of the group and Rune and Wren being the brains and experience.
Refusal of the Call/10-Minute Retirement: Chaz. Faced with the Great Light abandoning Algo and dumping the responsibility of maintaining the integrity of the Seal on its inhabitants, because that's solely what they were created to do, Chaz gets pissed and refuses to be treated like a puppet. He even goes as far as comparing it to the mindless devotion that Zio had in following Dark Force. He puts that aside when he meets Alis and the Elsydeon, and decides that even if it happens to align with the Light's plan, he intends to fight for the people of Algo who have struggled against the darkness for thousands of years.
Wren, being an older droid created for maintaining the system from an otherwise abandoned space station, is ridiculously human insofar as he has a human face, has hair, and is humanoid; he's also ridiculously tall and most of his body is geometric and metallic so he looks like he's made out of parts. Demi, on the other hand, is so human-like she refuses to install hardware into herself while others are watching and squees like a fangirl over big vehicles.
Robot Girl: Demi, though her behavior is quite human-like.
Sand Worm: The most powerful enemy you're likely to encounter during the early-to-middle stages of the game; they have A LOT of hit points and an attack which can quite easily result in a Total Party Wipe if you're not at full strength.
Sealed Good in a Can: The guardians on Rykros, and arguably Elsydeon, given that it contains the spirits of previous heroes that saved Algo.
Secret Test of Character: Re-Faze and the Anger Tower in Rkyros. Re-Faze does a pretty nasty thing by separating Chaz from his party, then forcing Chaz to fight a copy of Alys, his dead mentor. Then Re-Faze offers to teach Chaz Megid. If Chaz doesn't refuse, Re-Faze will kill him.
Shields Are Useless: Similar to Phantasy Star II, Shields take up a weapon slot as opposed to an armor slot, yet for most of your party (barring Rika, Hahn, Alys, and Kyra) the best weapons are two-handed, strongly encouraging a player not to use them at all.
This is subverted, however, by some equipment strategies for Rune and Raja that advocate them using two shields as opposed to their (only) other option, staves. While this does prevent them from having a basic attack, their basic attack is all but useless, anyway, and in exchange they become the toughest party members despite their low HP.
Dezoris makes some degree of sense, and Rykros (barring the structures) looks a lot like what a planet with an impossibly atypical orbit that spends the vast majority of its time exposed to pitifully tiny amounts of radiation from its primary ought to... though that then means that Chaz and Co. Can Breathe In Space, as the snow on the ground would be frozen air.
Status Buff: Several characters have skills to increase resistence, magic resistence or agility of your party. (as well as attack and critical hit rate) In later boss battles, the former skills are pretty much the difference between a balanced fight and a Curb-Stomp Battle.
One of the villains has his own special buff spell that makes him indestructable in battle. Finding a way to dispell it is part of the plot. Certain Mooks also use buffs, but since random encounters generally don't last long, those moves are often a wasted turn.
Status Buff Dispel: The Psychowand has the power to nullify all status buffs an enemy can cast on itself and is at one point the only way a certain boss battle can be won. The final boss also uses a skill that can tear down your defenses and it likes to do so before smacking you with its most powerful spell in the next turn.
This skill actually removes elemental resistances granted from equipment. Good thing that attack won't be doing even more damage than it would without, and nothing before this has it.
The Power of Friendship: Done subtly with Chaz. When it comes to technology and technical things, he has a hard time understanding... but he's very apt when it comes to understanding people, emotions, and relationships. The bonds he forms with the rest of the party are very clearly his source of strength, and witnessing the struggle of Algo's people becomes his motivation for fighting when he rejects fighting for the sake of destiny and the plan of the Great Light. At the end of the game, when Rune, the last party member to leave, is about to go on his separate way, Chaz is devastated at the idea of living alone.
Tin Man: Wren. He starts out as The Spock who has severe difficulty comprehending the logic behind the behavior of his humanoid travelling companions. (particularly the arguments between Chaz and Rune) In the end though, when he takes Rika back to Motavia to be with Chaz, he shows signs that he has gained some understanding of human emotion, despite not engaging in it himself. Even before that, he has an insightful discussion with another AI about the role of AI's in the human's lives.
Useless Useful Spell: Debuff and stun spells are still a bit of a liability, but unlike a lot of examples, instant death skills are effective enough to be used on a regular basis as long as you don't try to shortcircuit an organic enemy or shut down the nervous system of a robot. Instant death combination spells are a guaranteed kill for anything not immune. And, since many instant-death attacks have their own independent number of uses, they essentially cost nothing (in terms of what a party can bring to a boss fight) to use.
"World of Cardboard" Speech: Chaz's declaration against Le Roof, in which he points out the inherent moral failing of the Great Light's plan (to imprison the Profound Darkness using a seal it knows is flawed, and creating sentient beings whose sole purpose is to maintain it, and clean up whatever manages to leak out) and the accompanying hypocrisy (because Dark Force also charges its followers with mindless obedience to its will). Ultimately Chaz decides to go ahead and fight, not for the sake of the Great Light, but for the sake of all the heroes who died defending Algo, and for the people of Algo themselves.
You Cannot Grasp the True Form: The Great Light and the Profound Darkness to a degree. Descriptions and depictions of them are vague and allegorical, the manner in which they interact with the universe defies logic insofar as things we'd call their "emotions" and "thoughts" appear to have physical presence in our world (recurring series baddie Dark Force is described as the Profound Darkness' hatred and anger at being confined), and they work on such a scale that the Great Light's lock on The Profound Darkness' dimensional prison is Algol solar system; the efficiency of said lock is somehow related to Algol remaining in the form it was given. No one even tries to explain what's going on in the Very Definitely Final Dungeon, and in the fight with The Profound Darkness, the thing (which first appears as a sinuous black blotch amidst the psychadelic chaos) visibly disintegrates and reconstitutes itself several times over the course of the battle. The western version of the game does not go into any detail as to what fighting the Profound Darkness is supposed to accomplish and doesn't explain what happens once it's defeated.
The original version is a little clearer on this front. The Great Light and the Profound Darkness aren't singular creatures themselves. They're more like two opposing armies, comprised of spiritual beings who transcended physical bodies long ago. The inhabitants of Rykros are essentially members of that transcended race, and, being "fallen", the Profound Darkness has to assume a physical form to confront the heroes when they come to its prison-dimension, allowing the heroes to definitively kill it and letting the prison-dimension collapse on itself so that it can never regenerate again.
Zombie Apocalypse: This has happened to a village on Dezoris as a result of a mysterious plague; luckily you can find the cure (well, more kill the cause) and the people of the village who weren't dead yet recover while the zombified deceased find peace.