So a while ago I started a sci-fi book series that I want to either re-read or check to see if there are more books that have been released since.
The story revolves around two orphan boys who are adopted by two monster hunters who are really rich and at least one of them is nobility. One mentor is a brute named Asher who trains the bigger orphan boy. Of the two orphan boys one is more of a main character - in fact, his name has something to do with the names of the books.
The other orphan boy ends up being a half-giant and going to live with the giants for a bit and then later a school that has multiple other races, including trolls. The headmistress of the school is also a troll.
The main orphan is extremely intelligent and learns very quickly under the tutelage of one of the monster hunters, who has a military background. The main character's mentor is also part dragon or something along those lines and has some magical ability.
Also the main character was raised by a grandmother figure who was actually part dragon and really old. He was orphaned when she was killed by a 'red mage'. Red mages are the main antagonists. His 'grandmother' leaves him with a magical trunk with some artifacts inside of it
Edit. Some dragons decided to take human form long before the main story. The mentor not named asher is the one who is part dragon and he is able to turn invisible and is more of a roguish character that pretends not to care about anyone but truly does. I know there is at least 2 books and I read them about two years ago. I'm not sure when they were published but it is definitely post 2000.