Here is the full list of all 27 Skulls of the Shogun achievements.
Acquire 100 emblems.
Complete every level such that your best times for all of them add up to less than 4 hours on Normal difficulty.
Defeat 5 foes at once with a Salamander Monk's Lightning Storm spell.
Break a Deadly Alliance in online multiplayer.
Win a 4-player online multiplayer match.
Win an online match that lasts at least 30 rounds, defeating at least 30 enemies.
Complete the Forbidden Islands on Normal difficulty.
Complete the Land of Frozen Fortunes on Normal difficulty.
Earn 30 gold skulls.
Complete the Land of Golden Harvest on Normal difficulty.
Complete the Land of Monsoon Meadows on Normal difficulty.
Bring back a fallen unit with a Demon Fox Monk's Revive spell.
Win a team deathmatch game with your teammate still alive.
Win a multiplayer match with a 20-second-per-turn time limit.
Complete the Land of Eternal Blossoms on Normal difficulty.
Defeat an enemy Monk by haunting its Shrine.
Acquire your first "Very Rare" emblem.
Complete the Shores of the Dead on Normal difficulty.
Win an online multiplayer match.
Earn 15 gold skulls.
Power up your General to a Demon.
Knock 3 foes off a ledge at once with a Demon Crow Monk's Typhoon spell.
Earn 60 gold skulls.
Have an emblem upgraded to Gold status.
Complete the Forbidden Islands with 10 units or more.
Defeat a General with a Tanuki taunt.
Earn all 72 of the Bone-A-Fide Edition Gold Skulls.