Because every other forum was of no help to people who were not lore nuts, Im going to spell out how to get the zhukodim achievement. Start a solo game, set yourself as spectator faction and to team A, add 2 ais (also on team A) to fight 1 ai (any team but A) play until the 2 ai's beat the lone ai, get achievement.

Also the two Chaos achievements that are Apocolocyntosis, and Apotheosis essentially just kill enemies with chaos cultists, every time they kill an enemy they have a set minuscule chance to transform, can be slightly improved by killing an enemy while adjacent to the hero unit that improves chances of getting a boon of chaos.

Clarification: The two units that need to be transformed into are chaos spawn and daemon prince. These are also the only units that can be transformed into.