Here is the full list of all 25 Serafina's Crown achievements.
Kick off a romance with the fiery Roza of House Pajari
Complete your regency with Roza Pajari by your side
Start a romance with Kallias Jeridar, the prodigal former king of Darzia
Complete your regency with Kallias Jeridar by your side
Begin a romance with your trusted adviser, Arken Jeridar
Complete your regency with Arken Jeridar by your side
Initiate a relationship with Serafina and her husband Reuben
Complete your regency at the side of--or perhaps between--Serafina and Reuben
Embark on a relationship with the decadent Kendal of House Terrace
Complete your regency with Kendal Terrace by your side
Deepen your relationship with, well, someone...
Complete your regency by reconciling with your mysterious ex, no matter who he might really be
Accumulate 10 points with Picard, the god of pleasure and sensation
Accumulate 10 points with Belazar, the goddess of wrath and war
Accumulate 10 points with Demetral, the goddess of love and fertility
Accumulate 10 points with Mallion, the god of greed and wealth
Put Roza Pajari on the Darzian throne
Restore the reign of Kallias Jeridar
Make a king out of Kendal Terrace
Allow Serafina Elborn to become the next queen
Make your regency a permanent arrangement and ascend to the throne
Die an early death after breaking an oath
Defeat a god in a debate
Find the true killer of Queen Belatrix
Win a debate with opponent's score at zero