Crossover ideas thread

[Kat]

I secured a good beta, at least.

[Xamusel]

That's good, at least, Kat.

[demino_hellsin]

A horrible idea that haunts me my every waking moment. What if Shirou's servant was Kamen Rider Gaim instead of Artoria?

Not much is probably going to change storywise but the character dynamics would be hilarious. Gaim wouldn't be able to go above jimber because it would severely drain his master. His powers from the golden fruit would be mostly sealed by the Holy Grail. Archer would be stupefied when he learns what Gaim fought against as a hero and even more when he realizes Gaim comes from a children's show. And ofcourse who can forget? Gate of Babylon vs Fruits of Helheim.

[Cherry Lover]

OK, well, I have absolutely no knowledge about Kamen Rider, so I can't really comment on this very much. What would his reaction to Sakura be, though, or to Zouken?

[demino_hellsin]

Well as your bog standard hero, he definitely will save Sakura. His heroics go into naivety overdrive though because he doesn't believe in saving people by sacrificing others. Rather that's what he had been fighting against this whole time, the notion that you have to sacrifice someone to save another. As for Zouken, he would probably try to see some good in the old man, something to give him a reason not to kill Zouken until he realizes the Matou ancestor is nothing more than just a mass of negative emotions.

Gaim would definitely have the power to destroy the worms in Sakura's body, but likely her physiology would've been altered to be dependent on the crest worms so she'd die without them. Either way, if Gaim attempted to save her by removal of the worms, she'd likely lose her humanity anyway despite retaining her sense of self.

[Cherry Lover]

Well as your bog standard hero, he definitely will save Sakura. His heroics go into naivety overdrive though because he doesn't believe in saving people by sacrificing others. Rather that's what he had been fighting against this whole time, the notion that you have to sacrifice someone to save another. As for Zouken, he would probably try to see some good in the old man, something to give him a reason not to kill Zouken until he realizes the Matou ancestor is nothing more than just a mass of negative emotions.

Well, yeah, Zouken is unsalvagable, really. But, it sounds like he'd definitely try to help Sakura if he found out the truth.

Gaim would definitely have the power to destroy the worms in Sakura's body, but likely her physiology would've been altered to be dependent on the crest worms so she'd die without them. Either way, if Gaim attempted to save her by removal of the worms, she'd likely lose her humanity anyway despite retaining her sense of self.

This isn't true, she survives without them just fine post-HF. And, I see no reason why Sakura would lose her humanity just because someone removed the worms....

[demino_hellsin]

Oh, my bad. I thought just killing the worms would end up with her dead too. What did it need to remove all the worms again? I think it was surgery by Kirei?

Gaim has 2 possible methods at his disposal to kill all the worms inside Sakura. The first is letting Sakura breathe Helheim spores which have unbelievable growth capabilities, taking root even in living flesh to bloom. They can go from spore to flower in less than a few minutes. Despite being in full control of anything residing in Helheim, Gaim can probably guide the spores directly to the worms, grow on them then consume them fully before breaking down into base components. However because of the Grail limiting Gaim's abilities, he can't do this safely. The second method is to feed Sakura Helheim fruit which will force an evolutionary response in her body, basically mutating her, but Gaim can likely still help her control the changes so she won't become something monstrous. And the second path is the safer one 

Best case scenario, Gaim can somehow override the restrictions of the grail and regain his fullpowers. By that point he can probably just will the worms to die and completely restore Sakura's body down to pre-modification.

[Cherry Lover]

Oh, my bad. I thought just killing the worms would end up with her dead too. What did it need to remove all the worms again? I think it was surgery by Kirei?

Kirei removed most of them, but the one in her heart was too close for him to take it out without killing her. However, the issue with removing them is how closely entwined with her nerves and organs they are, not that she actually needs them to live.

Gaim has 2 possible methods at his disposal to kill all the worms inside Sakura. The first is letting Sakura breathe Helheim spores which have unbelievable growth capabilities, taking root even in living flesh to bloom. They can go from spore to flower in less than a few minutes. Despite being in full control of anything residing in Helheim, Gaim can probably guide the spores directly to the worms, grow on them then consume them fully before breaking down into base components. However because of the Grail limiting Gaim's abilities, he can't do this safely. The second method is to feed Sakura Helheim fruit which will force an evolutionary response in her body, basically mutating her, but Gaim can likely still help her control the changes so she won't become something monstrous. And the second path is the safer one 

Well, the first sounds like it might be somewhat dangerous, yeah. Even if they were growing only on the worms, those worms are filling spaces between her organs and nerves, so there's not really much space for a flower to grow. The second likely would work, but would be potentially very harmful, from the sounds of it.

Best case scenario, Gaim can somehow override the restrictions of the grail and regain his fullpowers. By that point he can probably just will the worms to die and completely restore Sakura's body down to pre-modification.

Yeah, that would work....

[demino_hellsin]

  I'm just working with what is in either series. Honestly if you want to blame anyone about the last one then blame Urobuchi. He's the one who wrote the end scenario of giving the hero absurd gary-stu powers XD

Either way the grail system is foolproof isn't it?

[Cherry Lover]

What do you mean?

[demino_hellsin]

Kamen rider Gaim was written by Gen Urobuchi. He decided to make it a free for all between kamen riders for literal godhood. Gaim won. So it's post series Gaim who is a god. But with the grail, his godhood is sealed. Unless he can bypass that protocol he's pretty limited.

[Cherry Lover]

Ah, I see. And, well, I'd certainly like him to have the ability to help Sakura, although I guess that outright godhood would not make for a very interesting story....

[demino_hellsin]

No it wouldn't :|

It would make for hilarity though when Gil finally decides to unleash Enma Elish completely and Gaim regains his full power just in time to undo the dimensional rip. Gil's face after that would be all sorts of funny.

For a serious crossover:

Final Fantasy Tactics X Fate Stay Night

During Tohsaka Rin's preparation for the 5th Holy Grail War, she had been stocking up on gems for her magecraft for the better half of her life. One day, while shopping for gems, she heard a rumor of of a set of 13 crystals being auctioned. They were apparently large as stone yet beautiful as jewelry. More rumors floated around that the stones were innately magical, each having a different color and symbol of the zodiac. This piqued Rin's interest so she joined the auction just for that set of gems. She bought the set surprisingly cheap. She had her heart set on emptying her pockets the moment she saw them presented to the bidders. However, suprisingly nobody wanted them. She only had to bid against someone once and that only upped her initial offer by 10,000 yen. It was after that she learned of the dark rumors circulating about the stones being cursed as everyone who previously owned them died a gruesome macabre death as it usually entailed their entrails being scooped out.

Rin ignored those warnings ofcourse and brought the stones back to her home to experiment with her magecraft. They had turned up to be inactive with her magic and through many failures, she ended up throwing the stones into the trash in her anger. However, she had missed one stone, the one marked with the zodiac sign of Virgo.

Months pass and Tohsaka is to summon her servant. When she performs her summon, it is unwittingly in the presence of the Virgo stone. Though she uses her own gem as a catalyst, things go out of her control very quickly. Her summon sparks and sputters before a dread chill fills the room. It vanishes as quickly when a loud crash can be heard above in the attic. When Rin goes to check what happened, she is surprised to find herself faced with a blonde woman armed to the teeth with a bow, crossbow, and sword resting against noble blue clothes and thick leather armor under a metal breastplate. The woman introduces herself as the servant Archer, true name Agrias Oaks.

Rin eventually figures out that Agrias is not of their world which should be impossible because of the way the throne of heroes works. But when she is asked to recount if there had been any strange things going on, Rin tells her servant the only strange thing she had in her house was a set of fake magic stones inscribed with the zodiac. Agrias reacts violently to this and scours the room where the summoning took place until she find the Virgo stone. Agrias explains that the stone was a holy stone from her world that was pure power with a fair bit of self sentience. It would be inert to anyone it did not resonate with. However, the stone was also a gateway for demons known as Lucavi whose goal was to summon a great devil, Ultima. Agrias asks where the rest of the stones are and Rin pales as she says that she threw them out. Agrias is innerved as Lucavi can be summoned by someone with an impure enough heart and restart the preparations of summoning Ultima once again. Rin then remembers about the gruesome murders and is informed by Agrias that such bloodshed is needed for the summoning of Ultima. Double bad as now Rin realizes that demons are running around killing people to power their demon god summoning while servant are killing people to power their own mana reserves and a the same time the demon summoning.

Life was just great for Tohsaka Rin don't you think?

[Cherry Lover]

Hmm, I see. Sounds like it could be interesting.

What would happen with Sakura here, then? Would she end up with one of the stones? Actually, who does have it?

[demino_hellsin]

Well I haven't the faintest clue who would get them. A lucavi summoning usually entails permanently possessing the summoner and outright killing him effect as the lucavi pretty much wears their skin.

If something were to happen regarding Sakura, I would imagine that she would undergo her Heaven's Feel transformation. Maybe have Shinji get a stone, turn him into a Lucavi and Sakura goes full on lesser grail then kills him. In Heaven's Feel, it seemed like Sakura was kind of insane with a plan, here she would just be plain insane. Partially anyway.

How I would imagine Gaim as a servant.

Servant Saber

Name: Gaim

True name: Kazuraba Kouta

Alias: Gaku Sano

Appearance: A young man wearimg a blue hoody with an orange armored samurai printed on the back. He has short black hair and brown black eyes.

Personality: Friendly and self-aware, Kouta is a very kind and forgiving person who hates conflict but has the determination enough to fight so others don't have to suffer. He is impulsive but has a fair amount of restraint especially when it comes to thinga related to battle. His outlook is very mature but his small wish makes him seem like a child.

Origins: Kouta is Kamen Rider Gaim, a fictional children's superhero from TV following a long list of predecessors spanning almost 50 years. He is known nationwide in Japan and in some other parts of the world, generally asia and north america. Under normal circumstances a fictional hero like Gaim should not exist however the story of Gaim is anchored heavily into the world by the fact he was played by an actual living person. This makes Gaim variably human and legitimate for summoning. The version of Kouta summoned is already the one at the chronological end of his story where he becomes a god of a new world. However he is not a true divine spirit as he is a fictional hero.

Parameters: Due to his status as a fictional hero, Gaim gains a rank down to all of his parameters.

Strength: E

Endurance : E

Agility: D

Mana: A

Luck: D

Noble Phantasm: EX

Class skills:
Riding: A

Magic resistance: B
- any spell less than a ten count aria won't affect him.

Personal skills:
Acrobatics: B
-In life, the actor that played Gaim had fair skills in acrobatics increasing his agility parameters by 1 rank.

Dancing: C
- In his lore Kouta was a former street dancer and has quite the talent for moving the crowd. He is proficient in modern hiphop and breakdancing.

Swordsmanship: C
- Kouta is a self-taught swordsman. Going with what works instead of following any real form or doctrine. Though he is proficient enough to make use of his raw power and match those with greater experience, he does not have the same proficiency as his fellow swordsman(Zangetsu)  to match and even overwhelm an enemy many times his own strength.

Healing Factor: E++
- Heals more quickly than most humans. When dealing with lethal wounds, his regenerative abilities can go into overdrive and save him from death. Sometimes even recovering him to the point of combat ready or fully restored.

Noble Phantasm:
Helheim: The forest that spurs conflict and evolution -- EX; anti-world
- As an overlord, Kouta can open dimensional rips called cracks to an alternate world known as helheim. Helheim is inhabited by a forest that grows without limit in terma of speed, habitat and size, capable of turning an urbanized world like earth into a jungle in a matter of years even with resistance. Kouta can manipulate these plants to attack or defend for him. The spores of these plants are easily spread and can grow practically anywhere? Even flesh. Fruits from this plant mutate anything that eats them and turns them into monsters known as Inves. Those inves who retain their sentience and gain the power to control the forest are known as overlords. Kouta can also control inves but not fellow overlords.

Henshin~ the miraculous transformation; sengoku driver and lockseeds -- EX; support
- transformative gear that Kouta uses to achieve his combat forms.
- orange arms~ take the spotlight! On stage: grants Kouta his basic armor and increases his strength, endurance and agility by two ranks.
- Kachidoki arms! ~ shutsuji! Ei! Ei! Ou!: Kouta's penultimate armor granting him access to his battleflags, katana-gun and a massive cannon-sword that can fire energy in multiple ways. This grants a massive four ranks and an active plus modifier boost to all of Gaim's parameters. Except for agility which only gains two ranks and no modifiers.
- kiwami arms! ~ Shutsuji! Dai-dai-dai-dai-dai-shogun!: the ultimate form of Kouta granting all the weapons of his previous forms in any number along with some others. He can wield them with higher output than their original counterparts in combination or even control them telekinetically. This form increases all of Kouta's parameters by two ranks and grants an active double plus modifier.

Quirks:
- as a servant that was summoned with an embodiment, Kouta has two sets of memories that barely mesh well together. Kind of like one person acknowledging two separate lives he had not known until recently. He is essentially both Gaku Sano and Kazuraba Kouta at the same time.
- as a servant with a base using a living person from the same time period, the world is much more forgiving to this phantasmal construct and puts barely any resistance in crushing it as it resembles an existence which should exist. This means it is more mana efficient to keep Kouta in a physical state than spirit form because spirit form would be regarded as more alien and prioritized for destruction costing more mana to resist.
- Kouta has a stronger signature as a human than as a servant making him impossible to find with a servant's senses. They would detect an average class mage rather than a servant. This allows him to mingle with the humans with almost no distinction. He still looks like the actor that played him though so some people would recognize him.