Here is the full list of all 12 Warhammer 40,000: Sanctus Reach achievements.
Kill 25 units with flame attacks
Kill 100 Orks
Win a battle
Win a sandbox game
Win a multiplayer game
Kill 100 Space Wolves
Kill 100 Astra Militarum
Kill 100 Chaos units
Kill a Freeblade
Kill a Morkanout
Destroy a Shadowsword
Destroy a Lord of Skulls