assassin_(learning_with_manga!_fgo)
One of the original servants in Riyo (lyomsnpmp)'s "Learn More with Manga! FGO". She first appeared in post #2538704. Depicted wearing a babydoll.
True Name: John Edgar Hoover, the first director of the Federal Bureau of Investigation (FBI).
Assassin is implemented into Fate/Grand Order as one of Super Bunyan (fate)'s Third Ascension partners alongside Rider. Assassin is voiced by Yonezawa Madoka.