Rei

He has always been a loyal dragon, regardless of how he might've looked at times from the outside. Having to live several lives essentially at the same time is certainly. Something that can make knowing his alliance certainly complicated. He is a good enough actor to make everysingle one of his different faces believable,so everyone does think they know the real him in some capacity. The true one is almost certainly though the first one, the one loyal to the ones generally accepted as the right side morally. And certainly an adept fighter that one is. Another one is an almost one in comparison, just a normal dragon working a normal job. Just some friendly face that will lend an ear to you if you're in need of one. And the third and last one is that of a spy coming from the perspective that's most often accepted as the actual one. But from the ones who know him like that? Just a fellow criminal, one who won't do anything irreversible without taking everything into account if another way is possible but is still willing to go rather far for the cause.
He can be brash and ready to take any risk for success, he can be a kind soul serving you coffee and he can be cold and calculated, but what he is without any mask? Without putting on any front? That's a question no one's sure they'll get answered in this life. He is loyal to the cause of defending his land, his home but what's going on otherwise? A good question.
One thing known to pretty much anyone that knows him well is his wish for revenge he has against someone who he has seen over the body of one of his best friends. The actual truth of that accident is certainly a giant mess, where taking into account he could do a lot of things if he would be able to work together with the one he hates it would be beneficial if the truth would come out at some point. Will it ever? Another good question which has a lot of other questions attached with how he'd react to the truth.
There is one who can understand him on a fundamental level, about living different lives at once. One who's one of the few he respects. Even if he does look like nothing but a hatchling. At least these two can get along and work together.
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Rei Furuya/Zero from Detective Conan