My biggest tip for fanfic writers is this: if you get a character's mannerisms and speech pattern down, you can make them do pretty much whatever you want and it'll feel in character.
Logic: Characters, just like real people, are mallable. There is typically very little that's so truly, heinously out of character that you absolutely cannot make it work under any circumstance. In addition, most fans are also willing to accept characterization stretches if it makes the fic work. Yeah, we all know the villain and the hero wouldn't cuddle for warmth in canon. But if they did do that, how would they do it?
What counts is often not so much 'would the character do this?' and more 'if the character did do this, how would they do it?' If you get 'how' part right, your readers will probably be willing to buy the rest, because it will still feel like their favourite character. But if it doesn't feel like the character anymore, why are they even reading the fic?
Worry less about whether a character would do something, and more about how they'd sound while doing it.
i was supposed to be cool and mysterious like sherlock holmes but instead I can't stop yapping about anything and everything that interests me in the slightest. like sherlock holmes
vein... is beautiful.
xia fei noticed it the first time they've met. long hair, so soft, yet in such brave colour. what a shame his hair is always braided. xia fei has never seen vein with his hair down. but he badly wants to.
vein is beautiful.
xia fei noticed it the first time they've met. playful eyes, looking at him. mysterious, yet kind. red eyes that see everything, even the slightest detail. long lashes cover them whenever vein's irritated, tired or amused by what xia fei's said. but sometimes, only sometimes, the red eyes are happily looking at him.
vein is beautiful, truly.
xia fei noticed it the first time they've met. vein's elegant clothes and the way he wears them. full of pride. full of grace. full of confidence. whenever he's passing by someone, their eyes follow him. and vein knows that because he knows everything.
vein is beautiful. but he doesn't look like that all the time.
there're these days where small dots of blood stain the white fabric of his shirt. it's not often, but it happens. xia fei pretends to see nothing because sometimes it's easier this way. vein never tells him what's going on. he usually puts on his long, black coat and tries his best to cover the blood.
that night when after a tiring day he'd finally came home, he's noticed he has a guest. and not just any guest. the familiar black coat hanging in the hallway. the elegant shoes in the hallway. and also vein's perfumes xia fei could scent in the hallway.
the bathroom light is on. the door is open. xia fei goes there.
vein is beautiful, yet full of mysteries.
in the bathroom vein stands next to the sink. the water is running down. however, the boss hasn't noticed him, yet. vein's too busy washing his dirtied by blood hands to care bout his surroundings. xia fei comes even closer, careful not to make any sound.
but he fails. vein instantly turns around and when he spots xia fei, something like embarrassment shows up on his face. only for a second. there's blood on his face, on his right cheek and forehead. but xia fei doesn't care because vein finally has his hair down.