Thread:Valeth/@comment-38196594-20190122002644/@comment-27971189-20190122094334

Yes.

Actually, it doesn't have to be homunculus (as shown by Shinji during UBW, and Apocrypha). Its just during FZ and FSN, Einzbern tried to cheat by making sure the vessel siding with them from start.

Further referenced by how Amakusa's Master portrayed in Apocrypha anime is not Grail vessel, unlike Irisviel and Illya.