Though I never have a problem with the guy since I have no interest with Knight of Cerberus, I would like to give you some tips on how to stop him due to some experiences. In my opinion, the best way to stop him is by (presumingly) report him to the community central & disabling his Yahoo Mail account so he cant make anymore trouble. My sister who had a Deviantart account once had a problem about this when some "female user" keeps posting links to porn sites by replying on her artworks, calling them "nice". She wasn't the only victim as there where many others. Most of them already reported that user to Devianart's community central & disabled but came back with a new account name everytime which is then disabled. The Deviantart users, including my sister have reported her again to the community central, this time to give her a warning from creating sock puppet accounts. The said person currently stopped by now.
............................................................................................................. Hey man, I wanted you to help me with an old enemy, do you remember the old guy who made the page Kurumi Tokisaki, he came back and he started to plagiarize a few pages from other wikis, he thinks just because he created some plagiarized page can think becomes ADM, this guy is really annoying so I started a campaign to ban this guy, I said stop plagiarizing other wikis but he ignored my warning and he said: I know and I don't care!! This guy sure is a danger to this wiki.
Good detective work, judging from the conversation that you had with him. He isn't a very nice person. I've dealt with him in the past too. What I recommend is that you ask Balthus, Amnestyy,Venage237 or MajinAbura to ban. He's just as bad as MarkelCraig and it's high time he packed his bags and left this wiki.
AH.. Do not worry about Markel, he was already redeemed, I talked to him one last time if he kept putting Knight of Cerebus on every page he saw I would ask for any ADM banish him, after that he stopped abusing that category.
Good to know that Markel's stopped giving us a hard time,anyway, sorry about not knowing that Venage is not an admin. I think we should link the conversation you had with User:Deidaramonroe and show it Magma. He'll know what to, and it will give Magma more reason to ban Deidara and he won't give us any trouble anymore.
He already has the link of the conversation offered by my friend DestroyerSubjugator, we are classmates. I tried to give him a second chance, but he is extremely lazy, he is obsessed by Kurumi, but I would leave Kurumi page here, she was one of the most famous anime villains of 2013, the problem is creator \ plagiarist of the page. He's so obsessed with her that he does not let anyone edit the page of Kurumi, is as if he thought that the page only if it belongs to him, and his profile is written: I will F*** who gets in kurumi's way. I have a feeling that this was an indirect insult to the users who edited the page of Kurumi.
What I'm saying is that he would not allow anyone to edit that page, when we added more categories, photos, information or templates he deleted our information. He was an extremist and plagiarist obsessed.