I've noticed that he hasn't been around all that much lately. I know that this is owing to the fact that he... really only cares about Kamui and Kotori and is, in general, not very talkative.
I think a nice way to build CR with him may be to abuse events? Maybe doing something silly like personality-switch or something that will make him interact with people. Or, just simply doing an 'accidental recording' of him reacting to other people's entries. I realize this one might be tricky since... well, maybe his only reaction would be to stare blankly at the journal. If you're stuck, just go for that, I think. I think that a lot of people here play characters who are sparkly enough to react to that kind of non-response, and then a thread can form from there.
Basically, I think that your Fuuma is fantastic, characterization-wise. But because he IS in character, he doesn't get a lot of opportunities to interact with people. For that reason, I think it'd be great to utilize the setting of Kiseki more or, barring that, take advantage of the plotting post or plurk to get some ideas on how he can make more friends.
So far, the event seems to be helping! I love seeing him interacting at the masquerade, and look forward to his reactions during the hunting portion.