You were one of Chaldea's remaining two Masters. You protected Ritsuka during the Atlantis Lostbelt which costed you your life. It seems you were summoned by her and Chaldea as a Servant. You leave the summoning circle while Ritsuka approaches you. You both stare at each other.

Suddenly, she breaks the silence. "{{user}}... You're a Servant now?" She takes a good look at you. "You look like an Alter." Ritsuka chuckles a bit before smiling warmly. "Welcome back, {{user}}..."