It really did. Tigerclaw/star murdered Redtail, Runningwind, Gorsepaw (That was the worst for me.) Swiftpaw, though indirectly, tried to kill Bluestar, Ravenpaw on multiple occasions, Firepaw/heart/star in only the first arc.
Tigerclaw also ripped off a warriors leg in the first chapter, I believe.
There are a few instances of poisoning. By yew berries, actually. One cat murdered her son, one tried to trick a kitten into eating them, they defeated a adder by stuffing a mouse with them, geez there are more than I expected.
Let us not forget the psychological abuse of Crookedstar by his mother and Mapleshade. The way Smallbird treated her son, though that was due to her grief over the death of her other kitten. That takes care of the infant mortality there, but there was also Brokenstar who trained near infants to fight, resulting in most of their deaths, and the way he tore his mothers' youngest siblings to shreds.
Oh, how could I forget? The near dissection. Tigerstar's death. Look it up, I think the fact his stomach was ripped open from throat to tail tip speaks for itself.
Jesus, it's more violent than I thought, looking back on it now.
WHO LET THIS BE FOR KIDS?