Here is the full list of all 7 Fantasy General II: Prologue achievements.
Complete an Onslaught campaign with Falirson.
Complete an Onslaught campaign with Filos.
Complete "The Curse" on Veteran or harder.
Complete "The Curse" on Very Hard.
Started "The Curse".
Won your first scenario.
Complete an Onslaught campaign with Ailsa.