Badass: His first major action in the first game is to walk into a monster-infested castle by himself (this is before he gains any of his dragon forms, by the way), head straight to the throne room, and beat the crap out of the boss monster, thus freeing the town. Things only go up from there.
Fate Worse than Death: Myria sends Ryu into one in The Dragon Warrior: the dimension of the Soul Eaters, who would slowly nack at his soul for all eternity, with him still conscious and unable to die.
Fusion Dance: Agni, the most power dragon transformation, has the entire party melding together into one being. It can singlehandedly take on Myria.
Guide Dang It: How to get most of Ryu's dragon transformation sets require having certain equipments with him, all of which are well-hidden all over the world map. There's no in-game mention of even what items one needs.
The elders living in the ruins where Ryu gets his training will tell him something like, "You need to complete the first level and find the DragonSD." But you still have to puzzle out where to find the equipment. The most powerful transformation is only mentioned once, on a tablet you can find in a well on the world map; it's quite possible to beat the game without ever finding it and get stuck with the "bad" ending.
Outdoor Bath Peeping: Ryu (and the player) get forced into this as a plot point: the Queen of Tuneland has the Time Key and intends to give it to Emperor Zog. The heroes therefore need to steal it from the palace vault before that happens. The combination to the vault is tattooed on the Queen's back, and the Queen spends every night bathing in the pool in her throne room. Ryu and the party sneak in and peep to obtain the combination, but because of the water's reflection they get it backwards.
Official Couple: Probably the only couple who gets anything close to a hint of having succeeded in the backstory of the second (and third) game.
The manga adaptations also plays up their relationship, including the Spin-OffLitle Adventurer starring their own child.
Our Founder: Or more aptly, "Our Hero". Ryu gets a nice gold statue in Camlon for his efforts in helping eradicate the monsters infesting the main castle.
Power Limiter: The Light Dragons have their powers sealed off in fear of how dangerous they were for the world. So, once the Dark Dragons have the upper hand thanks to Myria, Ryu is forced to go through trials in order to unseal his powers.
Voluntary Shapeshifting: Comes with being part of the Dragon Clan. This version of Ryu seems to be the most adept at it, as he can shift into a dragon form and stay that way as long as he wants without losing AP.
Back for the Dead: In the latter.note Thought it is subverted later, when there's a wolf-guy sitting on a rocking chair, and one NPC comments he was atacked by the dragon that appeared years ago. And there was no other wolf-guy in the prologue.
Canon Foreigner: In The Dragon Warrior manga, he gets 3: a wife, a child and a brother-in-law.
Doesn't have enough in his Mana Meter to back it up, though.
Also the spells start off very powerful, but they'll start becoming less useful later on, as he never learns any new spells. The later parts of the game will see him relying more on physical attacks, or fusions with Karn/Danc.
Master of Unlocking: His field skill is to open up closed doors and remove traps off chests and floors.
Play-Along Prisoner: After getting tossed into Auria's jail, the party is promptly let out by Karn, a fellow prisoner. Karn then goes back to sleep, indicating he could escape anytime, but took advantage of his 'incarceration' to catch some Z's.
Secret Art: Fusion. This was apparently the reason his clan's kingdom was destroyed by the Dark Dragons. You can find masters hiding in a few places and they will impart their wisdom to Karn.
Sole Survivor: In The Dragon Warrior manga, he's the only survivor of his guild of thieves, after a Dark Dragon raid.
Thieves' Guild: He was raised in one. After completing his introductory quest, the guild master says there is nothing more to teach him and even offers him leadership of the guild whenever he's ready for it.
Greed: A defining trait of his race throughout the series.
To the point where the resident thief of the party calls him out on this.
It's All My Fault: In Chapter 5 of The Dragon Warrior, he sells out an ancient and very dangerous weapon to Judas, believing it was just junk. He then gets shocked when Judas use it on the Dark Dragon's own town. This is what determines him to join the gang at the end.
Heroic Sacrifice: Sieg and Rai/Raifel, both in-game and in Princess of The Wings.
Mentors: Both Sieg and Raifel serve as Nina's instructors at the start of Princess of The Wings.
No Name Given: In the original SNES version and the English GBA re-release.
The Dragon Warrior manga averts it by giving the fist two the names Kalu and Ilu. Years later, the GBA port gives the three official names.
Odd Couple: Their characterization in Princess of The Wings: Sieg is the serious guard, following the King's orders and not too happy on letting Nina go on a dangerous quest; while Raifel is more easy-going, understands Nina's feelings to go help Ryu and disregards orders to help her in her goal.
Palette Swap: Sieg/Rai use the same sprite, while Enon is just a red colored swap.
Red Shirt: As a funny detail, Enon does use a red uniform, and he survives.
Shout-Out: They were given names in the GBA re-release, with Sieg and Rai being a reference to two characters of the Princess of The Wings manga adaptation.
Split Personality: She seems to suffer from this due to Jade's brainwashing. Specially notable right before her Boss Fight, as she at first creates a barrier to stop Ryu while gloating evily, then suddenly throws herself at it to destroy it and urges Ryu to continue...right before going evil again and attacking the group.
Stripperific: Near the end of The Warrior Dragon manga, courtesy of Bleu/Deis.
Clap Your Hands If You Believe/Emotional Powers: Her castle is apparently created by her mind/emotions, as its explained that the doors are closed as long as her heart is closed to others, and bringing in a memory from her happier childhood days with Alan makes her heart/the doors open again.
Raise Him Right This Time: One possible interpretation of the cutscene where the group finds child Cerl and Alan playing around, with the Time Key as the responsible. However, the really sad music and the fact both leave the screen and are nowhere to be found after the cutscene ends seems to imply otherwise...
Time Master: Thanks to the Time Key, she can do stuff like stop or fast-forward time.
Graceful Loser: For all the Evil Overlord act, he went down pretty gracefully, telling Ryu that, while he's done for, his dream is not dead and sending him off to go create a future for their clan.
Noble Demon: He wanted the best for his kin, in the end.
Large and in Charge: The concept art of Zog's Dragon form seems normal enough (compared to other Dragons in this series, anyway) until you actually get to fight him. Only his head was shown throughout the entire battle.
His normal humanoid form is taller than everyone else as well.
Orcus on His Throne: Basically spends the whole game sitting in his castle doing nothing till you come and face him.
Mood-Swinger: In The Dragon Warrior, he switch between a honorable warrior and an Omnicidal Maniac at the turn of a wrist. Later revealed he was kind all along, and his swings were caused by his internal struggle with Myria's brainwash.