Personally I prefer to not include myself or any characters of mine in a fandom, I am unsure as to why though. However, if I do make a character from a fandom, I'll typically use them to just sit around and occasionally have some nice roleplay or chat with fans and other people. I will however create characters based off of fandom characters, which I will roleplay and make them act more like who they're based off.
I suppose it's just due to a bit of an obsession of mine to try and keep intact the author's intention so as to not include myself into a fandom by creating characters based off a certain fandom, but not making them directly part of that universe.
I have created characters based/from the fandoms: (typically if I have a preset of them, I sit around on them often)
1-Marcello - APH, based off S. Italy or Romano
2 Flavio - APH, 2P! S. Italy (preset)
3 Pitch Black - Rise of the guardians (preset)
4 King Sombra - MLP (preset)
5 Sand - NWN2