Review Detail of Apns444 in Child of Destiny

Kid who was kidnapped at 3 years old, held in terrorist organization hideout and trained brutally for 6 years. Being beaten, forced to train, being brainwashed to be a mindless killer, being thrown into a room with all other kids and told 'last one to survive is free to go' and ends up being the last man standing. After all of this, SWAT raids the hideout and he gets rescued, not only does he have NO trauma, he acts like a grownup while talking with others, he trusts some random man to adopt him, agrees, goes home with the man and after 2 weeks of being there he GETS A FRIEND who is his age. How would a kid with past like that be able to trust anyone, not to mention make a friend? And to top it off, the 'friend' who is martal arts genius, who trained a lot, but only sparred, never had to fight for his life, somehow manages to fight the MC to a tie in a duel? The character design is very, very bad. His background is a massive plothole. No idea why the author would introduce a background like that, only to make the MC 'normal'.