10
I think he's around 30. Just a hunch but I don't think that they would send him to the palace if he's not adult, but I don't think he would be so much older than the seme
Maybe he was like 16 and now he is 26?
Maybe, but for me he seemed more mature than a 16 years old. But it is also true that he has not aged anything in 10 years ╮(￣▽￣)╭ Maybe he's an immortal dragon just doesn't know yet XD
So 10 years have past thats means the seme is 22 but how old is the uke?