Maybe 'Tower of God' is a good choice. Both have complex storylines and diverse characters.
You could try 'Solo Leveling'. It shares the theme of a protagonist on a challenging journey similar to that in 'Kill the Hero'.
One manhwa that could be similar is 'The Breaker'. It shares elements of action and adventure like Kill the Hero.
Well, 'One Punch Man' could be similar. Both have unique takes on the superhero genre and offer unexpected plot twists and powerful villains.
Try 'Lookism'. It shares some similarities with 'Villain to Kill' in terms of its diverse cast of characters and the exploration of themes like power and identity.
I'd recommend 'The Boxer' as it has a similar intense and action-packed storyline like 'The Desire to Kill'.
I'd suggest 'Tower of God'. It shares similarities in terms of the adventure and power-ups found in 'Kill the Dragon'. The worlds created in both are quite immersive and exciting.
I'd recommend 'The God of High School' as it has similar intense action and drama like 'Desire to Kill'.
I think 'The Gamer' could be similar. It has elements of adventure and character development like in Hero Manager.
I'd recommend 'Lookism'. It has a similar theme of underdogs fighting against odds and has engaging character development.
You might like 'Solo Leveling'. It shares elements like adventure and unexpected plot twists like Rental Hero. The characters' growth and challenges are quite captivating in both.
One manhwa that might be similar is 'The Supreme Warrior'. It has a similar theme of a powerful protagonist making a comeback.