I just removed it myself, but in the editor I use it lists categories like that on the right. You're probably using the VisualEditor though, so there should a dropdown menu to the left of "cancel" and "save page" that has a categories bit.
What's the best way to reach you, message Wall? I helped alittle while back with the character page. I wanted to help out quite a bit more, and bring in others that would want to keep the wiki updated. I'm currently quite involved with the subreddit, and wanted to better organize stuff with a wiki.
Also, I've been on Reddit quite a bit. I'm thinking that a forum is not the best medium for some discussions, like "what's the best character/build, etc." I think this would be best discussed on a wiki or page specifically for that character. I'm going to try and redirect some folks here, but it's also way out of date. There is a lot of content on reddit, and I would like to help getting it updated a bit.
Yeah, character pages use Template:CharacterInfoboxNew for the top stuff. Some pages have extra info in a tabber/table, like Venom. That's a bit more complicated and hasn't been converted into a template yet.