For the record Henry has Cap'n America; I have Kraven, Black Cat, and Invisible Woman. :3

[quote]Now say he writes a story or single scene involving those two. Are there any rules or anything he must follow in doing this? Or is it simply treated as interactions with an NPC in a normal post is?[/quote]

I'd say so, yes; since I control both it'd not be an issue and I'd just treat it as normal.

[quote]PiratePad[/quote]

Like TitanPad, it's sort of a group chat meets microsoft word/word processor that allows for cohesive and fast co-op posts.