[Prince Charon]

A template appropriate for some settings that might use this system (I'm not happy with the name of the template, though; suggestions welcome):

Communicable Caster (Psi) Template, 48 points:

Advantages
Evil Eye (Affliction; Disadvantages: Unluckiness+Weirdness Magnet, +25%; Based on Will, +20%; Malediction, +100; Astral Projection, -10%; Temporary Disadvantage: Phobia (Traditional 'witch banes') (12), -5%; Vision-based (User's Vision), -20%) 1 [21]
Spirit Communication 1 [8]
Dominance (Rationalization, +20%; Astral Projection, -10%) [21]
^ Wild Magic (Alternate Ability of Dominance; Cosmic Modular Abilities; Reduced Time 2, +40%; Astral Projection, -10%; Only for Allies with Summonable, -40%; Uncontrollable, -30%; Untrainable, -40%) 10 [4]
^ Spirit Magic (AA of Dominance; Cosmic Modular Abilities; Astral Projection, -10%; Only for Allies with Summonable and Minion, -50%; Requires (Attribute) Roll, -10%) 5 [3]

Perks
Dabbler (<base skill>, #; Spirit Communication, #; up to six other skills). [1]

Disadvantages
Code of Honor (Professional) [-5]
Sense of Duty (Apprentices) [-5]

Notes

This template's Dominance is activated by shaping a thoughtform, and sending it to possess and bond with the target. Will resists, though the target may choose not to.

'Wild Magic' is much like Potterverse 'Accidental Magic,' or most of Schmendrick's workings in The Last Unicorn (at least the cartoon version) - even when activated intentionally (rather than reflexively due to stress) you're basically saying 'magic, do as you will,' and hoping the spirit or spirits that manifest to 'help' you don't make things worse (they often don't understand humans that well, after all). The reason it has Reduced Time 2 is in case the GM decides to have more than one spirit show up. While Uncontrollable may be bought off, or swapped out for Emergencies Only, Untrainable should not be, as this ability represents power that you have little to no control over. Wild Magic should be at a higher level than your more controllable summoning power, regardless of whether the point cost is lower or higher, but need not maintain the 2::1 ratio in this example.

In nearly all cases, your style of Spirit Magic will be the same as or very similar to the one your teacher uses (the example above is merely a convenient placeholder), though you may change this later in life. If the Spirit Magic style is based on Demon Summoning, the other advantages above should also have the 'Corrupting, -20%' limitation, and the Affliction is likely to be rather different (id est, nasty and probably lethal (possibly changed to an Innate Attack), rather than strange and inconvenient, but probably not directly lethal).

The skills in the Dabbler perk vary based on style, though Occultism (if it isn't the base skill) and Spirit Lore are fairly common. Even if the base skill has no default, it will still be in the Dabbler perk, with an appropriate default to the difficulty level. If the base skill has a prerequisite that the target does not possess, that skill will also be in the Dabbler perk, at a higher level than the base skill (not all GMs will find that acceptable, but it seems fair enough in my mind).

Both the Code of Honor and Sense of Duty can be bought off, but others with this template who find out that you've done that will have less trust in you. Note that neither of these disadvantages prevents you from inflicting short-term harm on a student if it will benefit that student in the long or medium term. They don't even prevent you from having sex with you apprentice or apprentices, so long as you do not believe it will harm them. Of course, if you do cause serious or long-term harm to an apprentice, you will feel quite guilty about this, and should role-play that.