Hunter x hunter (2011) anime version you won't be disappointed its like naruto but people die even main characters. When you are watching a fight you are scared for that characters life and it makes it that much better. The main character is similar to naruto but the power of friendship does not save him when he's supposed to lose he does and his training isn't random bs.
Akame ga Kiru,
Cage of Eden- School trapped mysterious island with dangerous monsters, anarchy, suicides, homocides, and a cerberus.......LOVED IT!!!!
Psyren
It's a pretty decent list, actually, if you don't have characters of a certain significance in mind, man. These are the only ones I can recall off the top of my head where the characters dying are pretty important, though: