User blog comment:Xilinoc/Ch. 633 - FRIEND 3/@comment-24531362-20150702203705/@comment-26091912-20150706120932

^

That sounds like a nerfed version of The Zombie. Also, necromancy is communication with the dead; which is something all Quincy can do. (Never mind that Quincy can talk to the dead, they're at war with the Gotei 13).

Given everything we've seen about Robert: his abilities, personality, choice of weapon, etc. I'd say he's The Nimble. His unique ability would essentially be 'Superhuman Agility'; sounds pretty boring, I know.