Further extreme (but still possible) examples, how large would a people with size 100 be and how powerful would a race with magic 1000 be?
What does the "Life" category signify exactly?
Well, that's the kind of numbers that can't really be done. I'll have to cap it at 0.1-10 for now, there's a lot that can be done with it already.
As for the Life category. It's a body thing.
Body is determined by Size * Life.
So a creature with Size 2 and Life 2 will consume 4 times as much as someone with Size 1 and Life 1.
Life is power, muscles, fat, meat.
It also decides how well you regain Essence when possessing and draining them.
So a big and powerful body will be great for recovering Essence.
But it'll also take a lot of food to feed it, so you could have a suicide cult based around being eaten by that giant which is their god and creator.
Cannibalism is going to be a thing.
If you make a body with 1 on all except Size and Life (which will be 10), that will cost 0.1 Essence, grant 0.1 Essence every turn with long-term draining, or 1 Essence in a single turn.
But you'll have to have it eat 100 creatures worth to keep it up, so that's where the suicide cult comes in.
Do bear in mind you can only possess once a turn, so you can at max get 1 Essence per turn.
But a lot of god will notice your auto-cannibalism, and may find it... not pretty.
You can make the Essence body you possess have 0.1 on several other points, but there's side effects to that.
If Sacrifice or Worship is lower than 1, it'll slow down the yield of Power and Manifest. Having Worship higher than 1 only increases the worship you get from that one creature.
Having Sacrifice higher than 1 will increase the Power gain from every Sacrifice you do, but you'll have to do that personally.
Defense and Attack lower than 1 will be a bad idea, Magic lower than 1 makes it harder to do stuff. Fertility, Intelligence, and Skill will not be able to go below 1, no matter what.
This will make it possible to make a body with great sacrifice skill, but that's you, inside that expensive body, ripe for capturing and sacrificing.