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