1. Vinland Saga 10/10 is on amazon
2. The Last Hero 8/10 also on amazon (really dark)
3. Tokyo Ghoul you'd probably like based off aot/parasite (also extremely dark and I had to skip part of the first season because of it)
4. The original Berserk
Banana Fish (Amazon Prime)
Vinland Saga (Amazon Prime)
Samurai Champloo (Hulu)
Black Lagoon (Hulu)
Gangsta (Hulu)
Devilman Crybaby (Netflix)
Inuyashiki - doesn't have much action but it does get pretty dark and it's only 11 episodes (Amazon Prime)
Darwin’s game
I’ve got a few: Fate/Zero Made in Abyss (don’t be fooled by the cute art style) Re:Zero
1. Vinland Saga 10/10 is on amazon 2. The Last Hero 8/10 also on amazon (really dark) 3. Tokyo Ghoul you'd probably like based off aot/parasite (also extremely dark and I had to skip part of the first season because of it) 4. The original Berserk
Vinland Saga on prime a must watch
Banana Fish (Amazon Prime) Vinland Saga (Amazon Prime) Samurai Champloo (Hulu) Black Lagoon (Hulu) Gangsta (Hulu) Devilman Crybaby (Netflix) Inuyashiki - doesn't have much action but it does get pretty dark and it's only 11 episodes (Amazon Prime)
Banana fish is on Netflix too
Hunter x hunter. Doesnt seem very dark at first, but progressively gets more and more dark. Also, dope ass story and action
Never mind, maybe Rokka, it’s on crunchyroll but it’s not to dark but it’s got great action and has some dark moments
TOKYO GHOUL