BIODATA
Name:
Age: 17
Canon: Fate/Prototype Fragments
Canon Point: Beautiful Mind ACT-3, just before meeting Assassin
Appearance:
Canon Abilities: Tatsumi is technically capable of magecraft, although he doesn't know how to use it and would need training to do so. Mages in Fate/ possess magic circuits which are necessary to perform magic, of which he has exceptionally few - an E rank, which is the lowest on the scale, although their quality is ranked C which is at least modest. Basically if he trained seriously for a while, he could become a second-rate mage. As it is, he doesn't even begin to qualify as one at all.
His right eye is a Mystic Eye, which should normally come as a pair and typically to a far more capable mage. They tend to be seen as the mark of a strong lineage and power, it's a big deal, they come in all different kinds, having different effects. Tatsumi's is a Mystic Eye of Bio-Manipulation, which is able to control the body's functions. Assumably this could work on any living thing as unlike other Mystic Eyes, eye-contact is not necessary and works simply by being activated while looking at someone, even from a distance, perhaps even on multiple targets. Naturally, using it drains mana.
Of course, this is Tatsumi, so he doesn't know how to use it. He can activate it for a few seconds, but can only manage to paralyze a single target in that brief time. Moreover, he can't manage to do anything himself at the same time. Because he doesn't know how to use it, he also can't control it very well, and it can activate on its own through heightened emotions.
History: Prototype takes place in a sort of alternate universe to the regular Fate/ timeline, where the first Holy Grail War took place in Tokyo in 1991, as opposed to the fourth occuring around that time. The main difference besides this is that while the Grail was corrupted during the third war in FSN timeline, it's warped from the start in Prototype. While still sought after for reaching the route of magic and granting wishes, the real purpose is to summon the beast of the apocalypse.
Tokyo Grail War
Tatsumi is a high school student living alone in his recently deceased grandfather's apartment, while his family resides in Hiroshima (not out of any animosity, in fact he's very close with his younger sister.) He tumbles his way into the war by accidentally summoning the Berserker class Servant, Jekyll/Hyde, while reading his grandfather's notes. As it turns out, his family were mages some generations back and so a small bit of magic ability lays dormant in him.
After having the situation explained to him, the pair try to stop the Grail War from being carried out...and fail pretty badly at it.
They spend time scouting out the bases of operation of the other teams and at one point Berserker ventures into the garden of the Reiroukan estate, Caster's Master. There Hyde attacks Reiroukan's young daughter Misaya, as Tatsumi tries in vain to make him stop. Saber intervenes and finally Tatsumi is able to use a Command Spell to make Berserker retreat.
About two weeks into the war, the other participants band together to carry out a plan to separate and kill Tatsumi and Berserker, determining them to be a threat after the attack on Misaya. He's taken to Assassin, whose body is made of poison and is killed by her poisonous kiss. Caster brings him back to """life""" as a cursed Living Dead for Assassin to keep around, someone she can touch without worry since he's already dead. Luckily he's subsequently mercy-killed once more.
Personality: Doing the right thing and helping others is the most important thing to him, and he does it without pretense for his own image, unlike his Servant. As a kid he always pretended to be a real hero when playing with friends, and is terribly embarrassed to admit that he had the same idea when thinking about stopping the war - that he wanted to be "an ally of justice". Jekyll even compares him to his best friend in life who was known for being a particularly upstanding citizen and his own moral compass, a role which Tatsumi's given without his knowing it. He badly wants to see the good in others and insists on believing in them. He's a good kid, a really good kid. Even the people who straight up murder him realise it. He almost manages to convince Archer's Master, Elsa, not to play into the awfulness of the Grail War while talking to her, and she has a bit of a crisis because of it. Meanwhile she and Assassin both suffer quite a bit of guilt over killing someone so innocent.
On the other hand, he's prepared to do what it takes to stop the Grail War, even if that means killing the other Masters. It would be best if he can talk to them and get them to stop by making them understand what they're doing and how it's harmful to innocent people, of course! But he's been told that likely won't be possible, and he and Jekyll swore to one another they'd become the "monsters" themselves in order to stop the mages and the Grail.
He's pretty shy about things like taking compliments and girls. It bothers him that people, especially women, on the street notice Berserker, mostly because he seems to be enjoying the attention, while Tatsumi's too self-conscious to even be part of the attention by association. He can be a little self-deprecating now and then, because he doesn't believe in himself. When he's taken to Assassin, he has the opportunity to save himself, having been told he was going to be killed, but because she looks like a cute girl about his age, he doesn't feel threatened (and instead, nervous when she leans in to kiss him) and so entirely fails to do anything. But that's not only hormones talking, he's incredibly naive, which should be fairly apparent from his pure belief that they can in fact stop the war, despite both being useless. He trusts Jekyll implicitly despite knowing full well what kind of terrible things he's done, and that quickly comes back to bite him - somehow he's shocked when Berserker tries to kill the child of one of the Masters! Even the narrative of the Berserker team part of the story continuously warns not to be so trusting and to actually use his head.
But Tatsumi isn't terribly smart, so maybe he can't use his head. He isn't actually dumb, but he's exceptionally average in every way. From his appearance to his grades, he's nothing special, there's nothing that stands out in either direction. Some subjects he struggles in a bit, the others he gets B's, but he's pretty good at photography, but he's not an artist or anything. Just a typical teenager. The only thing he really has going for him is being so passionate, but that didn't come about until he got pulled into the Grail War. Until then he spent every day just the same as the last and did nothing of note and probably never would, so in a way, despite the circumstances, it's quite a thrill and turning point for him. Despite starting out nervous and afraid, willing to sit on the sidelines and leave things to Berserker, he's surprisingly brave when separated and confronted.