Darcia is a Noble. Oddly enough his left eye is that of a wolf's. He wishes to use Cheza to restore Harmona, his wife? I can't remember, but I think they were married. He does carry a gun. He kidnaps Cheza, but then in turn Cheza is stolen from him by Jaguara.

[If you haven't ruined it enough for yourself keep reading - Contains Images]

[Spoiler]

How does it end for Darcia?
He dies.

Does he die alone?
Yes.

What happens Spoiler-Girl?
Jaguara is Harmona's identical twin. Darcia points out to her, that she is only identical to Harmoma, by appearance only. She stabs him with her sword, poisoning him, but he still kills her, as is doesn't really affect him. Next time we see Darcia he's pointing a gun at Quent, and quent has his pointing at Darcia. Toboe's there too and he jumps in-between the two men. BANG Quent shoots Toboe, then Darcia aims for Quent again. Toboe gets a hold of his arm, and he informs them: 'Jaguara's poison is slowly gnawing away at me.' Toboe is still biting him. Darcia swings his arm unto Toboe falls off. Toboe's blood splatters everywhere. Quent shoots Darcia twice. Darcia shoots Quent once, and walks away.

"You are wolves that degenerated into humans and were kicked out of Paradise."

Later a dark wolf appears in front of the gang, he has one blue eye. It's Darcia! He's trying to turn himself into a wolf, and I'd say its working. He and Kiba fight for a bit. Darcia bites Kiba, and tosses him hard against some rocks, wounding him and he's down. Darcia wants Cheza, so he goes toward her, only to be faced by Hige, who's already injured. But Blue lounges at Darcia from the side. Darcia takes her down, and Kiba jumps in front of her motionless body. Hige bites Darcia's leg, he takes care of him, grabs Cheza, and runs off. When Kiba catches up to him, Darcia informs him: 'I will open Paradise.' They fight again, and Darcia has Kiba pinned down with his paw on Kiba's throat as Tsume comes from the side and bites Darcia, while Cheza jumps down a hole. Darcia knocks him away, but Tsume attacks again, but this time is fatally wounded. Darcia jumps down the hole after Cheza. Kiba comes face to face with Darcia one last time. This last fight leave Kiba heavily wounded, and the poison in Cheza's blood greatly affecting Darcia. Darcia walks toward the barrier between there and Paradise, but as soon as he touches it he's vaporized. All that remains is his wolf eye.