Hi,
I think one of the more recent book has a text relative to how to decide the might of a ghost. IIRC, it's equal to "highest ability score" for mundane ghosts and equal to "highst art" for magical ghosts.
But I can't find back the book.
I'm not sure which book it is. At first, I thought the church (but which page/chapter?) then Rival magic (amazon?) or was it in one of the ROP books?
Is someone aware of that ?
Thanks!
Nope, per RoP:M Might scores for ghosts are determined in exactly the same way as for any other creature.
When you design a magic creature I agree but here we are talking of the ghosts of a died human, and I'm sure there was a formula for this.
If it's current edition, my guess would have to be Calebais.
Amazon spirits p39 gives the formula for amazon ghosts. Found it back! Now i can extrapolate for any ghost finally.
(art for sorcerer and magic users like and highest martial ability/2 for mundane warrior)
Excellent! I'll be needing that soon as well, I suspect 
I know for a fact that the 2nd ed Calebais had some rules for this. I believe the Might of a magus' ghost was equal to Vim score. I have 1st ed but haven't read it all the way to the end, and haven't got the 5th ed book.