Universal: The strength of a soul is equivalent to the number of HD the creature has. Spells are a limited resource with usage die.
Method 1: Knave
Each HD of the soul increases the usage die of the spell by 1 step (ex. 1 HD = d4, 2 HD = d6, etc). Use Maze Rats spell generation of Beloch's magic words for more fun.
Method 2: Typical OSR
As above, but in reverse: the die size decreases with the level of the spell. Spell level is determined by target HD (Level 1 = d20, Level 2 = d12, etc)
Method 3: GLOG
Each soul has spell dice equal to its HD. These dice burn out on a 6 as normal, and are not replenished.
A soultrap is a sort of lantern built of celestial bronze and finely-shaped lenses. It costs 1000 sp to purchase and is only available in urban areas.To capture a spell, simply open up the trap as the target dies. When a soul is fully burned, a new one may be trapped in its place.
|I just learned about draw.io and it is well overdue.|
Stages of the Soul Cycle
The Sea of SoulsThe source of all souls, and thus of all magic. Numinous and unimpeachable in its existence without form or place. Saints and scholars have yet to come up with anything but illustrative metaphors to define its relationship with the material world.
EmbodimentA soul that has been integrated into a material form. All living organisms have some sort of embodiment, though not all are suitable for usage as a spell (it would be difficult to do anything with the soul of a bacteria, after all). The soul-bearing properties of non-living matter are a still a matter of debate and study - do all stones have a soul, or only those worked by human hands? Do cities have souls? Do rivers? What if you move water from one river to another? So on and so forth.
Working magic from non-living souls is difficult, so most thaumatologists will focus on the living.