it’s an old manga. the change on the anime was to tone down the story and makes it appeal to younger audience (the manga is highly adult only with a lot of bodies cut with lot of blood but because in the anime the ennemies are monsters blood was changed to vomit kind of green). The sad thing is that the manga is reaaaaaally, lots of action, tragedy, politics and highly deserve the Shaman King treatment of a kai version (even badly animated as long they stick with the story, characters personnality and background because it would be better than what we had)

Samurai Deeper Kyo, without a doubt and the anime is objectively pur trash. In the anime they changed samurai ennemies into aliens with sekigara battle becoming an alien invasion. In the manga we are in a classic seinen chanbara with light fantasy (the two biggest fantasy element are kyo and kyoshiro sharing the same body and nobunaga’s almost immortality with his body rotting).

even if its an unpopular opinion: slime season 3. It’s a transition season with a lot of meeting and not a lot of action but it’s ok because they are preparing for season 4 and the meetings are pleasant to watch.

I think we can add all JJBA openings and endings in the “no one skips” ^^.