Summon / Soul Power augmentation question.

So a big part of the game I’m translating from PnD (over a thousand pages and 10 yrs of development (currently on version 3.45) into a videogame format (a mix of normal videogame and PnD / Interactive Tabletop.), is a special core feature called a Dro. It’s a symbiotic spirit that grants magical effects (think a mixture of Persona from SMT Persona Series + Familiars from DnD + Mana from Mana Khemia.). What marketplace product, or node set up would I use to summon said Spirit and / or have it’s unique powers accessible dependent of progress bar (soul resonance) and character level?

Second question. Would this be an interesting system to have in a game if uniquely implemented? Or would it only be good as a background mechanic rather than a character driven one (I’m planning on testing the idea out on a focus group, but asking here would be a good gauge as well.).