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 World of Magecraft. He wasn't even aware of his inherited Mystic right eye until recently.
His mother, father, and younger sister, Tamaki currently live in Hiroshima while he lives alone in an apartment in order to attend school. He was a second year high school student at Setagaya High School.
Tatsumi was 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.
While he is a living dead, he shows some signs of his former self such as his sense of justice, however, he is still only capable of speaking a few words.
Tatsumi Kitano has brown hair, brown eyes and the average physicality of a boy his age. He normally wears casual clothes such as sports jerseys and runners. His Princes command spells are located on his left shoulder.
Fate/Prototype: Fragments of Sky Silver
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. After bonding with Berserker, Tatsumi spends most of the first half of the war using Berserker's Noble Phantasm to attack the Reiroukan estate.
On the fourth day of the Holy Grail War, the pair hear about the Miss Mary rumors on a late night radio program. The next day, Tatsumi hears rumors about a ghost in Akihabara. Upon discussing it with Berserker, the pair decide to investigate it that night. That night, Tatsumi and Berserker travel together to Akihabara to investigate the ghost rumours. While Berserker watches over him from a distance, Tatsumi searches for the ghost. Suddenly, Tatsumi spots a girl. Using his mystic eye on her, he grabs her and discovers Elza Saijo is the one he froze. Shaking off the effects of his mystic eye, Elza talks to Tatsumi and warns the pair about the dangers of being too naïve.
The next day, Tatsumi and Berserker meet with Lancer and try to get her help in stopping the Holy Grail War. After trying to convince her to let them meet her Master, Lancer refuses and leaves. Watching the spectacle, Elza Saijo steps out and scolds the pair; reminding them of their prior conversation. Elza then treats Tatsumi to dinner. During dinner, Tatsumi compares notes with Elza on the Miss Mary rumours. Digging in, Elza scolds Tatsumi for being naïve and not knowing anything about the Holy Grail War. Irritated, Elza tells Tatsumi to go register at the Holy Church in Ochanomizu. She then warns Tatsumi to be careful of the other Masters and leaves. Berserker later warns Tatsumi about being too open and defenseless.
Around 1 am on the eighth day, Tatsumi and Berserker attempt to assault the Reiroukan estate again. However, Berserker runs into Misaya Reiroukan. As he is about to attack her, Saber steps in and protects her. Backing off, Berserker and Tatsumi retreat. Later that day, Tatsumi heeds Elza's advice and goes to the church. Along the way, Berserker informs Tatsumi Kitano of the events from that morning and voices his concerns. Seeing the despondent look on Berserker's face, Tatsumi cheers him up and declares that he will stop the Holy Grail War. Reaching the church, Tatsumi insists on going in alone with Berserker telling him to be on guard. Tatsumi meets with the Observer (who is implied to be a younger Sancraid Phahn). There he tells Tatsumi that there is something he absolutely needs to know.
That night, Tatsumi and Berserker make another attempt on the Reiroukan estate. However, this time, Tatsumi is caught off guard when Assassin discovers his hiding spot. Attempting to talk to the girl, Tatsumi becomes overwhelmed with fright and tries to use his mystic eye on her. However, it doesn't work and Assassin kills him with her poison kiss.
Later on, Caster discovers his dead body and uses his corpse to reanimate as a girl. On the eleventh day of the Holy Grail War, Caster gifts Assassin with a ghoulified Tatsumi.
On the fourteenth day, the Living Dead Tatsumi tries to prevent Manaka from sacrificing Suzuno Yoshimori. However Assassin stops him and begs Manaka to spare him. Manaka eventually acquiesces and leaves Suzuno in Sancraid's care.
On the last day of the Holy Grail War, Tatsumi's reanimated corpse is killed again by Assassin in a act of mercy. As she kills him, Assassin confesses her love for him.
Tatsumi later reappears in Saber's dream which is set between Fragments and Prototype. There he reunites with Berserker and Assassin and parties with them, much to Berserker's shock.
Having become a Master, it is reasonable to assume Tatsumi possesses at least a basic knowledge of invocation ritual, having called forth a Servant. His right eye is a Mystic Eye, which turns red when activated and can stop the movement of anything that enters his field of vision. Similar to the Mystic Eyes of Petrification, it can be activated even without eye contact, such as through the viewfinder of a camera.
- Fate/Prototype: Fragments of Sky Silver Drama CD Bonus Novel 2: Heroes - Disk 2 Fragments 8: "Women’s Advice"
- Fate/Prototype: Fragments of Sky Silver Drama CD Bonus Novel 5: And so, the Holy Sword Shines - Fragments 1: "Not Here, Not Now"
- Fate/Prototype: Fragments of Sky Silver Volume 3: Beautiful Mind Arc - Act 3 Part 3
- Fate/Prototype: Fragments of Sky Silver Volume 3: Beautiful Mind Arc - Act 2 Part 1-C