Among the most hazardous spells in the maho-tsukai’s repertoire, this spell summons forth an oni from Jigoku. The oni appears anywhere the caster desires within the range of the spell, and must immediately be given a name - either the caster’s own name or the name of another person closely connected to the caster (a close friend, immediate blood relative, or someone who owes the caster their life) - or it will simply depart back to Jigoku. A name, however, anchors the oni into Ningen-do and allows it to remain within the mortal realm.
Once the caster has given the oni a name he must engage in a Contested Willpower roll against it. If the caster gave the oni his own name, he gains a +3k2 bonus to this roll. The caster may also Raise when casting Summon Oni to gain additional unkept dice on this roll. The GM should determine the Willpower of the oni : the more powerful the oni, the higher its Willpower. If the caster wins the roll, the oni will obey his commands (at least for now). If the oni wins the roll, however, it is free of control and typically runs amok until it is destroyed.
Naming an oni is a perilous business, for the oni will try to steal the name away and thereby gain full autonomy and the ability to remain in the mortal realm. Such creatures become Oni Lords, monstrously powerful, able to spawn lesser but still potent copies of themselves. Thus summoned oni will typically not immediately attack the persons who gave them names, seeking instead to leave them alive until they can steal the names completely.
Any person who shares their name with an oni will acquire an Oni Mark, a small discoloration on the skin. Every day the bearer of an Oni Mark must make an Earth roll to resist gaining the Shadowlands Taint as the connection to the oni corrupts them (see the Taint rules for more details). Each week they must make another Contested Willpower Roll, similar to the first, against the oni in order to avoid surrendering their name to it. The oni gains +1k1 to this roll for each Rank of Shadowlands Taint the Mark has infl icted on its bearer. If the name-bearer is the same person who summoned the oni, he continues to gain the +3k2 bonus to the roll, plus any bonuses from Raises on the original spell.
If the oni ever wins this roll it steals the victim’s name and becomes an Oni Lord, freeing itself from any control by its summoner (even if that person is different from the one with the Oni Mark). The now-nameless victim of the Oni Mark becomes a slave of the oni and must obey its commands. If the oni is destroyed or otherwise banished back to Jigoku, it loses its connection to the person with its name and the Oni Mark disappears.