User blog comment:Necor/Alcedia/@comment-32751919-20190116131946/@comment-33628324-20190116175732

just as his aka states, yes, it#s one of the two fire spirits he merged with, cuz in future there aren't enough humans alive that know/remember him as a "Hero" so he can't fully become a Servant by himself and fuses/merges with two Fire Spirits.