Here is the full list of all 23 Space Hulk: Deathwing achievements.
Complete Commandement branch
Kill 10,000 enemies
unlock all Assault Terminator's capacities in multiplayer
Complete Psy branch
Learn Vortex of Doom
Complete Devotion branch
Find all the relics
Kill a Broodlord
Kill an hybrid psyker
Kill a Genestealer's assault strain
Learn Inferno
Kill a Genestealer's warrior strain
Kill a Genestealer's stalker strain
Kill 666 enemies
Finish a chapter without using a Psygate
Destroy a door
Hack a door
Use the Psygate
unlock all Librarian's capacities in multiplayer
unlock all Heavy weapon support's capacities in multiplayer
unlock all Apothecary's capacities in multiplayer
unlock all Tactical Terminator's capacities in multiplayer
Make 1111 assists