Edward Teach

Blackbeard appears as the initial antagonist in the "Okeanos" Singularity, summoned in the endless sea created by the Holy Grail. His subordinates are Anne Bonny and Mary Read, Eric Bloodaxe, and Hector, as well as his own pirate crew aboard the Queen Anne's Revenge. Blackbeard used the Holy Grail he received from Hector to summon the Servants that aid him and developed an obsession for the goddess Euryale, who he wished to capture.

(Source: TYPE-MOON Wiki)