@Kzalca
Idk I don´t think it's fair to call the MC not right in the brain...
But i do agree its a great story so far :>
He started out depressed, but he wasn't suicidal or anything... and saying you are not right in the brain because of Depression isn't really fair in my opinion.
Getting over the fear of death is hard, but it is something soldiers are trained to do and also isn't that messed up...
A big part of doing so for normal people is finding something you consider worth dying for... something he clearly did early on.
Killing yourself when you are effectively immortal isn't really a question of morality, its a question about how much pain you are prepared to take to achieve your goals.
As for killing the flame emperor, yes he did murder the guy... but the man was an asshole and killing him was 100% for the greater good if you have read the novel.
Granted it is vigilante justice at the end of the day, but the manga also did a poor job to express how much of an asshole he really was.
So yeah, you can question his morality for killing a person who is an asshole and would go on to become at least a murderer of 2.
The novel hints at the possibility he killed a lot more people than just 2, but it never confirmed it.
But calling him "not right in the brain" for being
extremely determined and/or depressed isn't fair.