Dude's right for most part. Thunder had several of his alts banned or deactivated few years back and some or probably one of them have ownership of some pages quotes. Thunder has been exposed in the past for being the owner of these alts and that was about it. If you want further proof you can ask the admins who if they were on the wikia long enough know who Thunder is.
Uh, pretty lazy with going deep with looking for stuff, but there is a likely truth that you may own the alt. Its best to have definitve proof, but for now, you should be fine with pursuing with the quote thing.
If possible, you could try to send a message on my wall from the said account on a different wiki.