It's the classical D&D rules when it comes to HP. Fighterclasses 10 (xept barbarians 12, but that's not relevant here), priests 8 (interesting for Grace), thieves 6 and mages 4. Half if you've multiclassed, but your main char can't multiclass, so it's only relevant for NPC's like Dak'kon and Annah.

Übereil

Brain: an apparatus with which we think we think.

Ambrose Bierce