History: From the Harry Potter Wiki. Note that Evan died circa 1980-1981. I'm assuming he somehow ~*mysteriously*~ finds himself in Bete Noire regardless. Evan is also an extremely minor character, so some (or much) of what I write is personal embellishment. In addition, he will keep his memories of last time, which won't really be a big deal since that amounts to about... I don't know, two weeks at most.
Personality: AMBITION. Evan, in his time with the Death Eaters, was interested in power, not the anti-muggle propaganda. He was the first and only son of a fading house, determined to bring prestige to his family. At the same time, he was increasingly disillusioned with the way the "old guard" ran things and the various hypocrisies of the pureblooded class.
APATHY. It's a complicated subject fraught with controversy, but in general, Evan didn't give a crap who was muggleborn or not. To him, it meant you were backward and probably not as good as a normal wizard, and certainly pureblooded were to be given preference over muggleborn or halfblooded, but he wasn't interested in killing everyone. Then again, if that had to be the case in order to climb the ladder, so be it. As a Death Eater he killed just as many people as his comrades.
RUTHLESSNESS. Because Evan will do what needs doing, no problem. Even when he didn't really believe the dogma, he killed and tortured muggles and muggleborn wizards. It was not a "just doing my job" mentality, but a "sacrifices must be made" one with a touch of sociopathy. He wanted to be powerful and influential, and becoming a trusted Death Eater was the way to become so.
ROMANCE IS DEAD (MOSTLY). An incorrigible flirt who liked to go all out chasing girls, he enjoyed playing the part of a romantic while simultaneously being nothing of the sort. It was all a form of entertainment for himself, and he was a practiced charmer. He did have a lingering childhood crush on his cousin, Narcissa Black, which was why he never seriously chased her. She wasn't to be part of his games. His experiences with other males were never to the same magnitude and much more covert, mostly confusing encounters that didn't often repeat themselves.
MASKS. He's spent most of his life pretending to be something else out of duty or loyalty or ambition. A rebellious libertine pretending to be a dutiful son (or is it the other way around?), an indifferent yet power-hungry minion pretending to believe in discrimination, a disillusioned cynic pretending to be a romantic. Maybe it's more a matter of contrasts than disguises, but what Evan practices and what he preaches are often two different things.
Sexual Preferences/Orientation: As his journal name suggests, Evan is a bit of a libertine. While he does consider sex recreational and has a severe allergy to commitment, he is also picky as hell, choosing his partners for power as much as pleasure. He's not (intended to be ._.) the fandom stereotypical Slytherin slut trope; he's a thoughtful, ambitious, er, slut. Though bisexual, he ranks about a 2 on the Kinsey scale, exhibiting a general preference for women, with whom he's more experienced. He's capable of acting just as interested in anyone he thinks would be of use to him, however. Once he adjusts to Bete Noire and his new circumstances (i.e. being in the muggle world surrounded by muggle things and, well, MUGGLES), he may overcome his distaste for non-magical things.
Powers: As a Potterverse wizard, Evan is capable of using his wand to perform a multitude of useful and occasionally deadly spells, a list of which can be found here. Spells do not have to be spoken to be cast. He is an excellent dueler (though evidently not good enough to prevent himself from getting killed).