unb0und. While the general trend is that more powerful psychics attract more powerful spirit partners, the process by which that attraction occurs is mysterious, inexact, and only partially understood, even after literal ages of study. “What causes partnerships? What caused that spirit to bond with that particular human?” is sort of like that setting’s version of the god question in our world in its importance, how long it’s been debated, how humanity has yet to agree on a single answer, and how there are many different answers and even more interpretations of those answers.
That aside, what this means is that though a trend exists, exceptions can and do happen. Human/spirit partners can be mismatched in power level -- a human whose supernatural abilities are too much for the spirit to handle, or a spirit whose presence is too much for their human partner. If it’s the former, there’s a chance that bonding will kill the spirit partner; they might become overwhelmed during the process and end up not being able to maintain their boundary of self during contact, which can cause them to simply dissolve out of existence and revert to formless ether. If the bonding is successful, both the human and spirit will be weakened. The human will feel more drained by their abilities, since their partner can’t fully compensate for the energy cost. If the human partner overextends themselves when using their abilities, or if the spirit partner simply can’t keep up with the ambient drain of the human’s abilities, one partner could end up sapping the other’s vitality in order to maintain themselves (this can become fatal if left unchecked). While this isn’t an ideal situation, it’s not a death sentence, either; with effort and communication, a pair of partners in this situation can strike a balance and achieve a healthy life together.
The other situation is much more dangerous. If the human’s consciousness is overwhelmed, the spirit will spill over into their physical body and essentially overfill it, which can have potentially fatal effects -- a slowed or stopped heartbeat/bloodflow, dangerously high blood pressure, ruptures, internal bruising or bleeding, brain damage, and so on. If the human survives the bonding process, their abilities will increase in potency, but will also become more volatile and harder to control (the consequences of this can range from social disgrace to genuine danger to oneself and others). Frequent accumulation of built-up energy and the necessary discharge thereof will become an issue, and can have negative health effects over time.
There are also cases of people with supernatural abilities who never form a partnership, and people without abilities who do. People in the former situation are often prescribed medication that dampens their abilities and lessens the associated energy drain; Mu, who lost her spirit partner, takes said medication to compensate for having lost their energy, but not the augmented (and therefore more draining) powers from during their partnership. If the latter happens, the human partner is unlikely to survive; in the rare instance that they do, their life will be difficult and painful.













