I get it he had to at some point die. He was featured almost exclusively in the Halo comic Escalation which went really deep into a lot of who he is. Spartan ops in Halo 4 was basically Halo 4.5 featuring Jul. And also he was in a few of the books as well. So instead of doing cool boss fight or keeping him alive they just kill him half -Yoink- in the first mission. Personally i think it would’ve been better to keep him alive and progress his character a bit along with his story of being the Diadacts hand.