This is Holt, originally a gang member in Castelia City before things went south and he was eventually beheaded, and thrown into the sea. Eventually brought back from the dead as a Dusknoir; he wears a gold ring around his neck to keep himself from (literally) losing his head and his torso when opened seeps out air/energy from the Spirit World. Holt currently works as a Bounty Hunter, looking for fugitives either dead or alive. When not doing bounties he’s usually spending time in the Underground, either in the Underground Battles or various shops/bars hosting down there.
Other facts: He doesn’t have eyeballs, the “pupil” is a glowing orb of light traveling between both sockets. If he loses his head, his body will continue functioning just fine whereas his head will remain inanimate. The lower-half of his body can detach from his torso “mouth”; unlike his head both halves will continue to function perfectly fine.