Here is the full list of all 17 Sigi - there are A Fart for Melusina achievements.
Find the long lost golden grail.
Find the long lost golden talisman.
Find the long lost golden crown.
There she goes again.
Defeat Ivan Stinkup.
An apple a day...
Collect 1000 coins.
Defeat Kolles Terrol.
Defeat the Steel Horse.
Kill 100 Zombies.
Defeat Blind John
Fart at Melusina.
Clear all caves.
Collect all SIGI's.
Hard to find and almost out of reach.
In under 30 minutes?
Pocket 2500 coins.