1. Fullmetal Alchemist
Fullmetal Alchemist is a hotbed for debate within the community. While differences crop up all the time, Fullmetal Alchemist completely diverges at episode 25. Overall, the 2003 anime adaptation is darker and more political than the manga and Brotherhood remake.
2. Akame ga Kill!
Believe it or not, but more people die in the anime than they do in the manga, and there is a little more emphasis on comedy during the earlier episodes. That being said, the biggest difference is the anime’s exclusion of the Wild Hunt Arc.