I really like what you've written so far; it really draws me into the story.

For your main character's personality and motivation, I really see him as someone who will endure a lot of hardships without complaining, and will do anything for his sister (who's the only person he loves, as his parents are dead, and he's been secluded in the orphanage for his whole life).

If you ever decide to rewrite the prologue, I would suggest that you go deeper into the emotional and physical pain of being experimented on, and maybe highlight that his determination to do well and persevere in all his training is so that one day, he could get out of the orphanage and find his sister, so that when he gets adopted, it's like his wishes were suddenly granted. You could also make any scenes where he gets lost a little funnier (like him wandering around in circles, while bystanders wonder what he's doing).

Did you know this story is from Royal Road? Read the official version for free and support the author.

A little proofreading would also help enormously.