ok so while I am quite far, I do have a question that will probably make me look like a total noob, do the companions level up, and should I be using essence on them, and if I should be using essence on them how do I do that?
Companions do level up when you win with them accompanying you, you can also reallocate their stats and they'll keep whatever ratio you gave them. To give them essence you need to first put essence in their inventory using the button with arrows going either way at the top left of your inventory screen then use the essence from their inventory screen, and yea if you want them to actually be useful I'd recommend giving them essence and upgraded weapons.