Something that has always allured me to a series is where the MC starts off a weakling, but then due to certain circumstances, they grow, and change. Becoming darker and stronger. Series like Tokyo Ghoul and Tower of God.
@Jammin Do you have any suggestions?
Hmm. So you want something where the protagonist starts out weak and then shifts to being strong with a mildly dark flavor.
I can think of a couple options that might be in that ball park. The series that come to mind are...
Kuro no Maou (Translated Japanese novel)
It's one of those person transported into another world stories except much darker than most. Where the protagonist is transported over and then subjected to experiments. Nice gradual buildup of the main character here who is just an all around good guy who gets trapped in crappy situations on after the other. The plot is also pretty good though very unusual. The main hook is the very entertaining Yandere harem. He's like a magnet for sociopaths. Pretty much every girl that falls for him is a Yandere. Every single one. So they are super nice and act like angels to him but straight up murder people who trouble him in the background. It's a pretty fun read.
Great Demon King (Translated Chinese novel)
This is one of those Chinese reincarnated with your memories intact stories. Where the protagonist is transported into the body of a slave serving in what is essentially Hogwarts for necromancers. As you can imagine he quickly rises to be a superbadass necromancer and dark wizard. The main hero is also not nearly has antihero-esque as he may sound. He's generally a fairly good guy.
Overlord (Translated Japanese novel, manga, and anime)
This is one of those MMO becomes reality series. The twist being that the main character is the lonely and mildly insecure guild leader of villain/monster role playing guild. Which results in a lower management office guy stuck in the skeletal form of his Lich game avatar and in charge of a now sentient group of evil custom NPCs his guild mates created who practically worship him as a god; all of whom find themselves in a new world. The downside here is that the growth is more character-centric than strength. As he is OP as hell right from the start. But you'll find a lot of character growth in this. Both from the MC, as he tries to figure out what to do, and the various NPC's, as they slowly adapt to being self aware.
There are a lot of versions of this. I would order them Novel > Anime > Manga. So I would suggest checking out an episode of the anime by Madhouse and if you like that at all it go pick up the
Official Yen Press version of the novel. That's the best version IMO.
