Spiritmancy

Oftentimes, a person might feel great dissatisfaction and regret when their life comes to an end, and their essence may linger in the living realm as a ghost, an invisible force that's unseen to most.
Spirit summoners aid in exorcising ghosts by contracting with them: they form a contract that provides sufficient mana for the spirit with the ability to manifest itself, and in doing so the deceased gradually undergoes a sense of spiritual catharsis. Their restless form gradually becomes stable, and their memories return over time, as they come to peace with their life (if the spirit summoner is successful). The spirit then passes on.
Spirit summoners undergo rituals and training to allow them to see, and communicate, with what would otherwise be invisible, mute ghosts. While a normal magi might look at the aftermath of a battlefield and only find corpses, a summoner's sight allows them to view the many wandering, lost ghosts, formless and suffering through despair in the face of death. This ability is called spirit sight.
Beyond the fundamentals of spiritmancy, more advanced forms exist where the summoner can enact a séance to target and commune with a specific spirit. This typically involves intimate knowledge of the deceased, who is--if a magi--more often than not, stuck in purgatory. Loved ones of the target (if available) join hands around a purgatory mirror (made of soulsteel), that the summoner gazes on as the connection forms, and they peak into the realm, calling out toward the spirit. If the ritual is a success, they'll appear alongside the spirit as an astral projection in purgatory (but may still speak to others present in the living realm).
Summoning is a lot more difficult than communicating with them. It requires a strong, binding contract, and an offering of the spiritmancer's very life force to maintain the target in the living realm, usually for a limited amount of years.
Advanced Spirit Summoning - Hidden Ability
Cost of 10RPP. Must have spent RPP on spirit summoning. 
This allows the spiritmancer to form a contract with one magi spirit that's in purgatory:
* They are directly bound to the summoner, and can be forcibly dispelled if desired. This connection may grant quirks such as an emphatic link, minor telepathy (emotionally charged thoughts), and the summoner is able to track the spirit to their location.
* The contract expires after a number of years, usually 5 or less, depending on the specifics of the ritual, and the summoner cannot form another contract afterwards for the same amount of years that the spirit was maintained. So if a spirit takes 3 years to pass on, the spiritmancer will need 3 years to recharge their lifeforce for another summoning ritual.
* It is rare for the deceased to take the form of a spirit if they died of natural causes, or their own free will. Someone who dies smiling, or with a strong resolve that their death was worth it - such as to save a friend - is unlikely to hear the call of a spiritmancer while in purgatory. Only spirits with strong regrets form contracts.
* It's dangerous to summon a spirit if they only recently passed. This risks distorting them further than they are in their spirit form, making them completely amnesiac or even failing to take shape at all (often harming the spiritmancer in the process). Most summoners wait at least three years to minimise these risks, but the more time the better.