There are a few pictures of him when he looks fully corrupted as well as ones with only his face like in that picture and one with only his arms but that picture looks the best in my opinion 
[img]https://img09.deviantart.net/8918/i/2011/214/3/1/bb_death_claw_by_nightmarezenuki-d42g43k.png[/img]
[img]https://t15.deviantart.net/tcjj9nf5h2PAUVnvfaVdgi5lPxM=/fit-in/700x350/filters:fixed_height(100,100):origin()/pre10/3fb4/th/pre/i/2017/077/7/a/bboc_shadow_hayate_undead_warrior_by_brunozillinhero-d924d3h.png[/img]
just imagine his arms are black as well and I'll probably make him a Neko and have his body survive the battle and have him become a heartless that way