I don't know enough about MtG to know how bullshit Convoke is, but everyone who does seems to think so, and who am I to argue against them? Soul Stone, when combined with whatever the Summer Raiment redux will be will let us pull of a very convincing Magic Girl disguise, but I'm not totally sold on its overall usefulness. Maybe if we could bind the ghosts to new bodies down the line it would be more appealing, and would appeal more to my biopunk sensibilities. Hallowed Haven is neat, and it would be nice that we know we can enforce non-violence in an area, but the part of it that serves our magic economy is not as good as Convoke there, so it loses. Knight's Oath would be great with a large, trust worthy team, but this is still set of time so it won't get much use right away.
Of course I'm also very tired and unfamiliar with the setting, so I could be completely wrong. But I don't think I am.
Funnily enough, I'm basing Convoke's power mostly on the description given: at the cost of making a willing target tired, it produces mana that can be used on spells or Constructs. Additional info:
-Plants always count as willing, but tapping them with Convoke uses their reserves of energy, and thus means the plant may be more vulnerable to disease and weather changes, amongst other things, for some time afterwards. Plants have a slight gain in size and mana production when the mana they produce with Convoke is fed back into growing them.
-Constructs degrade over time, fast enough to prohibit tapping a person mutliple times during their lifespan. Constructs can be dismissed to speed up the recovery time of those tapped to produce them. Destroyed constructs don't do this, damaged ones that are dismissed do so proportionally to their remaining mana.
This opens up a rather large array of options, in and out of combat. In particular, it potentially lets us tap into the power of a massive number of people to help us beat Gretchen, and gives us easier access to power when we need it. Need to heal an ally or injured bystander, but our usual mana sources have been tapped? Get a donation of power from another bystander or ally. Want to fix someone's illness? Have a loved one, or multiple loved ones, donate the energy required (a service we could offer quite easily, and get tons of good PR in return, at the risk of becoming Panacea). Want to grow a tree? Tap the grass around it, or all local weeds/invasive species/clinging vines/undesirable flora. And potted plants are now portable sources of power, too.
It's a simple power, but it opens up a vast number of options and possibilities. It's quicker and easier to use than most of the proposed super-spells, and one we'll likely use frequently and with minimal effort involved. It comes with the fewest caveats and the least investment of time in getting it to work. And yet it's still a very powerful tool that we can apply in almost any situation.
