Well, revenge can be seen as a theme too. There are characters who are seeking vengeance for past wrongs done to them or their loved ones. Also, the exploration of different forms of magic and power is a significant theme. The various characters possess different magical abilities, and how they use or are used by these powers is an important aspect of the story.
In general, the Dorohedoro anime is quite true to the manga. It captures the key elements and the unique style of the source material. Some small adjustments might be made for better visual presentation or to fit the animation format, but they don't deviate much from the manga's core.
The Dorohedoro anime ends approximately at a certain point in the manga, but it's not an exact one-to-one match. Some storylines might be slightly different or left out.
En is a very complex character. His power and his role in the world of Dorohedoro are quite fascinating. He has a certain arrogance, but also a vulnerability that you don't expect at first. Shin is also interesting. He's a bit of an enigma, always seeming to be in the middle of things and having his own motives that are not always clear. He's got a mysterious air about him that draws you in.
The 'devils' in 'devils guard the real story' are very much a mystery without further context. They could be the product of a creative mind's imagination, designed to add an element of danger and mystery to the story. They might be inspired by traditional devil - like figures from mythology, such as Lucifer in Christian mythology, with all the connotations of evil and temptation. Or perhaps they are a new and unique creation within the story, having their own set of characteristics and motives that are yet to be discovered. Maybe they are not even living entities but rather some kind of inanimate objects or forces that are personified as 'devils' for the sake of the narrative.
In a Dorohedoro crossover with 'One Punch Man', Saitama would be an interesting addition. His overpowered nature would contrast with the often - more - gritty and complex power levels in Dorohedoro. Another good character could be Guts from 'Berserk'. His dark and brooding personality would fit well in Dorohedoro's gloomy atmosphere. Also, Edward Elric from 'Fullmetal Alchemist' could bring his knowledge of alchemy and his quest for truth to the Dorohedoro world.
I recommend the following novels to you:
1. "The Enchanting Demonic Concubine, City-Toppling Beauty" tells the story of a woman named Felier's growth and love in the demon world. It involves elements such as demons and demon gods.
2. "Lord Demon God is Too Enchanting": It tells the story of a profligate young master named Ye Xuan who became a Demon God and fell in love with a Demon woman.
3. [Cute Rabbit World: A story involving a rabbit demon. The protagonist is a rabbit demon who has lost his memory. The story also involves elements such as demon kings and demon gods.]
4. "The Primitive Spacetime Demon Lord": The protagonist traveled through time and space and became the Time Demon God, involving elements such as Demon Gods and myths.
I hope you like my recommendation. Muah ~