Blonde/White-Haired Guy with big sword in red trench coat has a lethal foe yay relationship with brother in blue coat with katana. Are we talking about Ragna and Jin or Dante and Vergil from Devil May Cry?
During Ragna's story mode, Platinum accuses him of being a paedophile, before calling him 'Aqualung' in reference to the well known Jethro Tull song.
Spiky silver hair, red trenchcoat, giant sword... that screams Sanger Zonvolt.
Jin shares his most notable traits with Suigintou. Including having an existing Rivalry with the main characters. As well as having a "Suigintou" Color Pallete in Calamity Trigger.
Nu-13's overall appearance and emotionless attitude is a reference to Barasuishou. Both wears eyepatches (Albeit, Nu-13 can only be seen wearing an eyepatch in her "Younger Form"), both are clones of the originals, and both only show their emotions towards someone important to them.
There is a shout-out to Star Wars, of all things, in Ragna's Continuum Shift Story Mode when Jubei tells Ragna of Kagutsuchi.
Jubei: The 13th Hierarchical City of Kagutsuchi. You will never find a more Wretched Hive of scum and villainy.
Another Star Wars shout-out occurs later in the game during Rachel's joke ending, when she equips Ragna with sunglasses that make every woman in Kagutsuchi (and for hilarity purposes, Jin) fall in love with him. Kokonoe's description of Bang's reaction to Litchi declaring her love for Ragna is "as if millions of voices cried out in anguish, and were suddenly silenced." Though there may have been a bit of playing with the fourth wall, there too.
CS's "Help Me! Professor Kokonoe!" segments can be seen as shout outs to the Tiger Dojo Fate/stay night, as they're both only viewable upon attaining a bad ending, they're much more lighthearted and comedic in tone, and they both tell you how you screwed up and how you can get it right next time.
There's at least one shout out to Ken Akamatsu's Negima hidden in both games. Some fans speculate that Ishiwatari and Akamatsu know each other and are fans of each others' works.
A pretty large one is that Rachel Alucard to Evangeline, possible right down to the Expy level. However, her cross shaped attacks are more reminiscent of Remilia Scarlet. Considering though that Evangeline herself may be an Expy of Remilia Scarlet, this may just be a recursive sort of thing.
Arakune used to be a normal being, but he is now some sort of Eldritch Abomination. He is litterally consumed by madness, he isn't aware of what he is doing, and he repeats lines and lines with the same word over and over. In Story Mode, one of his losing scenes shows him as a creepy swirl repeating "Azure" ad nauseam. The resemblance with Giygas from Earthbound is striking.
Before you dismiss it too quickly, bear in mind that BlazBlue has a healthy sense of humor.
Fate route probably gets shouted out by... Bang, the overly idealistic 'Hero of Ikaruga', who is way too eager to follow his master's footsteps, and had a nearly impossible dream of winning Litchi's heart, same way like Shirou who is dead set to follow Kiritsugu's footsteps as a 'Hero of Justice', and never gave up loving Saber, even when she went back in time and die there. Most agree that even when Litchi joined NOL, Bang's love to her never dies out, and only time will tell if True End gets shouted out.
Unlimited Blade Works main shout out would come from Jin, after the discovery that he is the world's antibody and that Hakumen is his future self, resulting him losing his insanity (or traded it with a different one), similar on how Shirou starts seeing a harsher light of his ideals thanks to his future self Archer, who is the Counter Guardian of the world (similar to antibody). Hakumen himself became bound with the orders of Rachel, same way like Archer became the Servant of Rin... who has the same seiyuu and voice actor like Rachel.
Heaven's Feel has elements of it running already. Tsubaki, being the lover of Jin who stays on the dark due to a jealousy with someone else (Noel) is similar to Sakura, the lover of Shirou on the route, becoming Dark Sakura as she is jealous with Rin. On the other hand, Litchi started to mirror Shirou in the case of her joining NOL to save Arakune even after knowing that they're run with bad people is the same like Shirou completely tossing his ideals aside to save Sakura; and in the same time, Litchi has become something like Rider during her tenure with Shinji, a Fetish Fuel Station Attendant lady fighter who is deep down good, but is saddled with a cruel superior. Bang's involvement may also be seen as a reference whereas Bang is like Shirou while Litchi is like Sakura, as it is believed that Bang's Nox, Phoenix Rettenjou, is the key to save Litchi from corruption, same way as how Shirou used the Rule Breaker to separate Sakura from the Dark Grail.
The plot of Carl's joke ending resembles the "six mysteries" event in Kingdom Hearts II... with added hilarity. The sound of a crying girl in the restroom? That is the School Nurse Litchi trying to get into a miniskirt one size too small. It also references Detective Conan, for obvious reasons, and even Scooby Doo, since one of the group members calls them "Mystery Inc."
One of Ragna's costumes in Calamity Trigger bears semblance to The Joker.
Genesic Emerald Tager Buster references to Genesic GaoGaiGar. Tager even gets a GaoGaiGar pallete as DLC.
Speaking of color palletes, Tager als has one referencing The Big O.
Makoto's full of Street Fighter references. While her fighting style is already similar to Dudley's, her Unlimited mode pretty much gives her his entire moveset (and taunt). In addition, her Astral Finish is an over-the-top version of the Seichusen Godonzuki, an attack used by hernamesakeMakoto. Unlimited Makoto can also perform the Abare Tosanami.
They're two Hospital Hotties with leerings to Hot Scientist (Litchi was before, Kyoko was after) with long black hair. They had an occasion wearing a lab coat too (Litchi on the back stories as her scientist days, Kyoko wears it all the time, even in combat), and both wear glasses all the time. They're also teachers (Litchi taught the Kaka clan, Kyoko is a Badass Teacher)
Both tangled/sided with the antagonist faction (NOL and Justice High), but their true personality seems to leer to actually good hearted people.
Though they seem professional/kind most of the time, when nobody's looking, they tend to be Lady Drunk (Litchi as seen in Noel's CT Joke End and Tsubaki's Gag Reel, Kyoko's All There in the Manual).
They're surrounded with two guys, one intellectual and so far is the one winning their affection (Arakune/Lotte Carmine and Hideo Shimazu), one Hot Blooded guy who probably had one-sided crush on them (Bang Shishigami and Hayato Nekketsu, the latter of whom teamed up with Kyoko and Hideo in Project Justice)
For fun, during Carl's Gag Reel, what role does Litchi took? School Nurse, just like Kyoko.
Noel could be seen as an alternate Dizzy slapped with Millia's color. Or the game's Cammy.
Rachel is essentially a female Slayer. In a wink from the creators, Rachel and Slayer even share one of their KO poses.
Likewise, Arakune combines both Zato-1/Eddie and Zappa, with a dash of No-Face.
Litchi is pretty much the combination of both Millia Rage and Anji Mito. She gets her powers in similar way as Millia (Boundary corruption and Forbidden Beast), and her relationship with Arakune mirrors Millia and Zato/Eddie, as well as them leaving their former posts (Sector Seven and Assassin's Guild). And just like Anji, Litchi is closely related to a pink-haired woman who is rather vengeful (Kokonoe as a stand-in for Anji's Baiken), wears glasses, and CS development had her join NOL, coming in conflict with Kokonoe who hated Hazama/Terumi... same way as Anji joined That Man, coming in conflict with Baiken, who hated That Man. Though consensus also say that despite being on the enemy side, they also have yet to turn into complete evil.
If Potemkin were a cyborg devil, Tager would most likely be the direct result.
Ragna, however does - in the fourth Teach Me, Ms. Litchi!!!, Ragna even complains about his low defense, and Litchi explicitly says it's "not as bad as Chipp Za-", while her thought bubble had a silhouette of Super-Deformed Chipp.
Hakumen's entire character fighting style is based off an older Daisuke Ishiwatari game, The Last Blade, back when he started at SNK. He plays much like a Power character from that series.
During one of CS's "Teach Me, Miss Litchi!" segments, Noel comments on how she had been trying to make herself smarter for her studies, and brings out the. "Ludovico Brain Flex-O-Matic model 1984." She said she saw an ad for one in a magazine and ordered it from the Orwellian Industries website.
For an old school Shout Out, Hazama/Terumi has a lot in common with Richard Wong from Psychic Force. Both lived in a Crapsack World steered to satisfy their desires (Terumi feeds on hate, Wong always seems to get the happy ends for him). They can manipulate time and highly think of themselves as in the world's most awesome person. They manipulate a 'dark, antagonistic but may be well-intentioned' group (NOL and NOA) for their own purposes... with eyes closed. They also at one point turned a good Shrinking Violet member of the good guys into psychotic evil people (Noel and Emilio). And while Hazama is on his way to screw a hot female scientist (Litchi), Wong already screwed a hot female former scientist (Chris Ryan, turned into the combat cyborg Sonia, that he canonically got killed by the second game)
And coincidentally, Jin shares the same birthday (Valentine Day) with Keith Evans, who is the resident rival and ice user of Psychic Force.
Said in a very commanding and serious tone, Makoto's victory line at the end of a match parodies Fist of the North Star.
A possible reference in the English version when Hazama finishes of someone with his astral heat he will say "Please, just die for me".
One of Arakune's winquotes is translated in the dub as "What is a man?"
Tsubaki also seems to have similarities to LancerTrope CodifierKain. They're both the best friend of a more important character (story-wise), they are both more skilled fighters than said friend (Noel needs Bolverk to fight, whereas Kain deals more damage than Dark Knight!Cecil due to his Jump), and yet they are both ranked lower than their friend on account of favouritism (although, granted, Cecil was the king's adopted son while Noel is the victim of a Manipulative Bastard), and in both cases The Lancer is jealous of their friend's close proximity to their Love Interest. Also? Their respective Face Heel Turns are for the most part due to Envy.
Platinum's Astral Heat is almost identical to Marisa Kirisame's "Surefire Spark" spellcard from Touhou Hisoutensoku.
Litchi is called an "oppai obake" (lit. boob monster), the exact same nickname that Vita has for Signum
During Plantinum's encounter with Ragna, while insulting him Luna randomly calls him "Baldy." This is probably a shout out to Bleach's Hiyori, another bratty character who likes calling people "baldy" regardless of whether they actually are.
Another possible Bleach reference: one of Hazama's favorite insults is "trash." This is the signature insult of prominent villain Ulquiorra.
The #14 swap in Chronophantasma exchanges each character with another.
Ragna <-> Makoto
Jin <-> Izayoi
Hakumen <-> Tsubaki
Noel <-> Nu-13
Mu-12 >-> Lambda-11
Rachel <-> Valkenhayn
Taokaka <-> Arakune
Tager <-> Bang
Litchi <-> Amane
Carl <-> Relius
Hazama <-> Platinum
Bullet <-> Azrael
The #15 swap is a recall to Persona 4 Arena where Persona characters dress up as BlazBlue characters, but since not all BlazBlue characters were represented... italics refers to BB characters using the palette of those not playable in P4A.
His personality in joke endings is influenced by Gintoki, with whom he shares seiyuu. Both Ragna and Gintoki are badass white haired swordsmen whose fear of ghosts makes them scream like girls. It is implied in the materials collection that Mori asked Tomokazu Sugita to be Ragna after he watched Gin Tama. This inspires various Blazblue x Gintama MAD videos.
Jin's brother may be the one who looks a bit like Archer, but in terms of what their job is...he pretty much fills in the role as a Counter-Guardian. Jin is described as the world's antibody after all. He's probably still in the Emiya Shirou phase, however.
Considering how the Nasuverse reference spree goes, Rachel filled in for Rin Tohsaka; not only she has the same English and Japanese voice actresses, she also summons and is essentially Archer/Hakumen's master. Then again, she looks more like Arcueid Brunestud...
On the other hand, her playstyle is identical to Order-Sol's.
Again with the Nasuverse references, she seems like the stand-in for Sakura Matou, being the most likely of Jin's love interests. She's also turned to the dark side (into a Green-Eyed Monster, precisely) due to frustration of someone (surprisingly, not the Rin counterpart Rachel) taking everything away from her.
Platinum has a male personality, a female personality, and a third personality which is ridiculously powerful. Hmm. What we're facing here is a loli Ryougi Shiki. RUN.
Her actual character design is an over-the-top parody of Sailor Moon.
Funny little note, if one notices, the third personality of Platinum is Ryougi... but in reverse. Where Ryougi can, more or less, destroy anything that she comes across being the personification of Akasha, Platinum's Trinity can create... anything. The odd thing is that Ryougi can recreate... anything... however this is a power of Akasha that she doesn't use all that much.
Makoto is an expy of Squirrel Girl, and her fighting style is very similar to Dudley's from Street Fighter. Her Unlimited mode takes this to its logical extreme as she gains several of Dudley's moves, and even a variant of his taunt where she throws an acorn at the opponent.
On the subject of Ace Attorney characters, Relius seems a bit reminiscent of Manfred Von Karma, as both are stoic and obsessed with achieving perfection, both are abusive towards their (adopted in Von Karma's case) sons, and even try to kill them when they get in the way. They are also very refined, and wear cravats. Not to mention their voices are both deep. All that's left now is for Relius to become a lawyer.
Saya appears to be the Aizen to Hazama's Gin at first.
In Jin's Arcade Mode in Continuum Shift. When he's resisting Yukianesa's influence on him, he says "Urusai!" three times in a row. Does this remind you of a certain Fiery RedheadedGirl who is also an aloof Tsundere and wields a Katana?
Take a look at his Astral Finish, then notice the pose he takes afterward. He must've learned a thing or two from Akuma.
If you listen closely to his story mode dialogue in Japanese, you'll eventually realize that Kakihara is pretty much channeling Jun Fukuyama's "Zero voice". It makes even more sense considering his mask, which looks chillingly similar. He is even more reminiscient of Nightmare Of NunnallyZero. This comes full circle when in CS he gains a Zero palette! All Hail Hakumen/Jin! and the realization that Hakumen's voice is based off of Lelouch's Zero Persona.
One of his palettes gives him red armour and blonde hair, which together with the green sword trails may remind some of another Zero.
One wonders if his name and Kitsune theme might make him a shout-out to the Big Bad of Ushio And Tora, the kitsune daiyoukai Hakumen no Mono.
According to Word Of God, Ragna drew inspiration from another wanted man in red, Vash the Stampede. Also, there's stuff like the psycho-brother, dead female companion, (Rem may not have been Vash and Knives' sister, but damn close enough) the robot arm and the wing that comes out of his arm.
Noel is one to Guilty Gear. In one of her story mode paths she's forced to dress as both a Jellyfish Pirate and later Valentine's outfit.
Her entire fighting style is an homage to Equilibrium, from which many of her moves are explicitly taken.
This might be stretching a bit, but consider the fact Taokaka is a Genki Girl voiced by Chiwa Saitou who doesn't wear pants... doesn't that also describe Francesca Lucchini? (Yes, the pantsless bit is important.)
A few references to Wolverine as portrayed in the Marvel vs. Capcom games, such as Hexa Edge resembling Berserker Barrage X or both having supers that create a double.
On the subject of Fullmetal Alchemist, Hakumen can be seen as a reference to Alphonse considering he's actually Jin who sealed his soul into an Animated Armor. Plus both mention their brothers quite often.
They might remind some of Tarvek and Anevka Sturmvoraus from Girl Genius. Mysterious father whose experiments have screwed up the family and who has provided a body for the Big Bad, sister transformed from human to something not...
He may also be a reference to JoJo's Bizarre Adventure, particularly Part 3 (on which the fighting game adaptation was based). As in the JoJo fighting game, the Carl player effectively controls two characters at once. Marionette Purple even sounds like the name of a stand.
Nu's armour design is reminiscent of Anubis. Specifically, the pointy ends of the legs combined with the wings. Now, if the armour had dog ears and a staff...
Hazama's Astral Heat has the same input as our dear Geese Howard'sRaging Storm. Geese's Raging Storm releases a series of shockwaves blasting above upon execution. Hazama's Astral Heat conjures a series of chains blasting above upon execution. Coincidence?
Tsubaki's Astral Heat is one big homage to Lenneth.
During Arakune's joke ending, Jin's shop has Sol's Fuuenken sitting on the table.
In Continuum Shift, Jin gains Fatima's color pallete: ◊
Relius Clover's Astral Finish is just one big shout out to hentai in general. The place looks like a crazy sex dungeon, the opponent is tied up (or in the case of Hazama/Tsubaki, totally willing / completely oblivious), and the doors close before anything can be seen or heard. While this may seem creepy the fandom has already started making fun of it, even going so far as to call it the greatest troll finishing move of all time.
In Bang's case, he has cinderblocks placed onto his knees in order to break his legs. This is a Shout Out to Darkstalkers, where this was the signature super of Bishamon.
Azrael's Astral is more or less a FalconPunch, with the addition of a scene afterward where he flashes his exposed back to the screen like Akuma.
Azrael also borrows a mechanic from a past Arc Systems Works game, as his Valiant Charger special incorporates Hokuto no Ken's Boost mechanic. Anyone who's familiar with the fighter probably shat bricks when they saw that, but fortunately, he can't lock you into an infinite loop with it. Well, he could originally, but they patched that out.