You might like 'Tokyo Ghoul'. It has a dark and gritty tone with morally ambiguous situations, similar to the themes found in Death Note. The storylines keep you on the edge of your seat.
One manga that's somewhat similar is 'Monster'. It has complex characters and a deep, twisting plot like Death Note.
One manga that could be similar to Death Note is Monster. Both have complex storylines and deal with themes of morality and justice in a thought-provoking way.
If you like Death Note, you might enjoy 'Tokyo Ghoul' and 'Parasyte'. They have elements of mystery, action, and moral ambiguity. 'Tokyo Ghoul' explores the struggle of characters in a dark and violent world, while 'Parasyte' delves into the theme of humanity and the unknown.
You might want to check out 'Re:Zero'. Both have unexpected plot twists and engaging character developments similar to 'Instant Death'. Plus, the art styles have some commonalities.
One manga similar to Death Note could be 'Monster'. It has complex characters and a psychological depth that keeps you engaged.
I'd suggest 'Clannad'. It shares elements of heartfelt storytelling and explores various emotions, similar to what you find in 'The Promise'. There are touching moments and character arcs that might strike a chord if you enjoyed 'The Promise'.
You could check out 'Sword Art Online'. Both it and 'Gamer' have elements of gaming, adventure, and character growth in a virtual setting. However, they also have their own unique twists and differences.
One manga that could be similar is 'Elfen Lied'. It has elements of dark fantasy and complex character relationships like Narutaru.
I'd recommend checking out Fullmetal Alchemist and Berserk. Both share elements of deep plots and intense character development like Death Note and Code Geass. They also have dark themes and epic story arcs.
Well, Tokyo Ghoul could be one. It has that intense and mysterious plot like the ones you mentioned.
You might want to check out 'Naruto' and 'Bleach'. They have similar levels of adventure and drama. Plus, they feature diverse characters and engaging story arcs that can give you the same kind of enjoyment as Code Geass and Death Note.