p.s. The fued between you and that other guy is a bit silly. Why not just let it be? So forget about him, and know that calling him our, and threatening to make is life miserable kind of makes you look like a jerk.
Well out of curiosity I followed the link to his (ugly whatever the rest is) guild website with "TOS" link, ie troll on site. This told me heaps about him and the people he runs with, and will answer your question "Why not just let it be". Just sayins all.