Here is the full list of all 12 RISK Factions achievements.
Earn 10 stars and trade them for 30 troops
Control 5 capitals
Defend a minimum of 5 attackers with 1 defender
Be the first to get an objective in a game
Defeat someone in online multiplayer who has earned the Man Up! achievement
Kill 100 human, cat, robot, yeti and zombie units
Complete the human, cat, robot, yeti and zombie campaigns
Achieve 10 super overkills
Play 5 games online
Win a 5 player online ranked Command Room game
Win a game on each map
Win 10 online ranked games