When Loki steals the guys eye for hawk-eye in Avengers he kills (sacrifices) the guy on a Moloch altar go look ill wait.
In Marvel Comics lore, the Chitauri are a race of shapeshifters who seek to subjugate all.
Loki sacrifices to Moloch to open a portal for shape-shifting ayyys to subjugate humans, in return he gets to rule earth.