Just a few years back I remember looking up Fairytail Role Play and during that time nothing appeared, but maybe a few sites. However, each of them were not very good sites. By not good I mean they had bad layout, bad skin, bad skin colors, and not much options. Your best bet at the time was to find one that was at least active and bare with it. However, most of them died VERY quickly. However, not recently in the past year that a spike of FairyTail Role Plays have been sparking up. Some of those old sites came back and revamped for the better. Most of the older ones died because of admins personal reasons.
However, these newer sites are doing OK. There about maybe four on top of my head I can think of FairyTail role-play sites that are fully active and some are active and growing. Of course, not including Wiki Role-Play section, but sites like Proboards, zetaboards, and invasion boards. If I am not mistaken, three of them are cannon only sites. Meaning they're sites you Role-Play as Natsu, Erza and so forth. However, me and you both know sites that active or been around for a long will have the major cannons are taken. Most likely the admin him/herself have taken your favorite one or just the one you wanted. Or perhaps, taken the strongest one of the FairyTail.
Which is Zeref, of course. However, some of the ones I have seen of Zeref is showing him as a true evil bad ass, but in the manga it was more passive and polite. He didn't really want to kill until last bit of the chapter where he was ticked off. Everyone else I seen in some sites he's a sadist or he has control over his death power. Though, we cannot say how much power he has over it, but so far we have seen he cannot. However, I saw one certain FairyTail Role-Play which is none cannon and allow people to be creative. While also you cannot be too sure how powerful someone is just by their exp count. If your bored and want to try something new. Make a character and make him bad ass from being evil, good, or in between this site is for you. It called FairyTailz: Deadly crows.