|Japanese name:||來野 巽|
|Appears in:||Fate/Prototype: Fragments of Blue and Silver|
|Character type:||Human, Master|
|Master rank:||Rank 7–Princes|
|Circuit Quality:||Rank C|
|Circuit Quantity:||Rank E|
A high school boy who lives in Setagaya, in the metropolitan area. He was raised like any other ordinary child without the knowledge of the magic world. He wasn't even aware of his inherited Mystic right eye.
Tatsumi is considered, by the people around him, to be an ordinary young man, both in grades and sports. His hobbies were bird-watching and reading. The only thing that he had pride in was in his photography and animal watching. His favorite food is Japanese Spanish Mackerel.
He wound up becoming involved in the Holy Grail War after unexpectedly summoning Berserker with his deceased grandfather's mementos that had been sent to him by his parents.