Summoning magic 「召喚魔法, shōkan mahō」 is a branch of magic that involves summoning an object or living being, sometimes from another plane of reality, and requires mastery of spatial magic to perform. The most common uses of summoning magic are to summon daemons and — less often — elementals or monsters. The most rarely used summoning magic would be summoning otherworlders simply because of the sheer time and effort it takes to prepare for the summoning. Almost all summoning magic requires a relatively high amount of magicules to execute, and always involve some kind of contract or deal with the summoned individual.
Master lock[]
When a being is summoned and a contract is made, the summoner is considered the master of the summoned being for the duration of the contract, with their authority over the summoned being taking the form of a Master Lock 「製作者命令, masutā rokku」. While secondary masters can be assigned, so long as the master lock is in place, the summoner is considered the "prime" master, whose authority over the summoned being supersedes all others. Proficient summoners are able to deactivate the master lock and transfer their authority over the summoned being to another person, though it will automatically return to the summoner if this other person dies.[1]
Known summoning magic[]
Daemon summoning[]

Although daemons are largely considered the embodiment of evil, they are surprisingly useful when it comes to executing a plan, since they are known to value a properly approved contract. Thanks to the summoning contract daemons cannot betray the summoner, given it is reasonable. However, any request beyond the original contract automatically annuls it. This is because if such an act is done, it testifies that the parties involved are not satisfied with each other.
When summoning daemons, the summoner is required to provide some kind of sacrifice. This can be in the form of pure magicules or living sacrifices. Since daemons are constantly attempting to become stronger, either can contribute to their future growth. However, in most cases, the compensations presented also used as a means to construct at least a temporary body, since as spiritual life-forms, they will disappear if they are without one in the physical world.
Naturally, the stronger the daemon is, the higher the compensation and magic need to be to summon and create a contract with them. Even summoning a lesser daemon can utterly drain an A-rank Adventurer, such as Thegis, the instructor who tests Rimuru for promotion. If one offers too little energy in the process, the daemon might try to kill the summoner, although, that kind of thing can be fixed with a proper contract by providing it with adequate magic energy.
Higher ranking daemons are also harder to control and bind under a contract. One must be adequately prepared since higher-order daemons, such as archdaemons, who are known for their high pride and unwillingness to follow a master, or else they might ask for ridiculous reparations or such compensations that might ruin the whole point of establishing the deal, such as the Primordial Red Rouge who annihilated the summoner's country right after destroying their opponent.
Elemental summoning[]

Summoned elementals are usually harmless and have little to no sentience, working only by means of an abstract kind of will or directive. However, it is also possible for sentient elementals like Ifrit to exist as well. Although, such elementals are usually very high ranking and, similar to Daemons, unlikely for them to willingly serve and help just about anyone.
Equipment summoning[]
Information to be added.
Monster summoning[]
Information to be added.
Otherworlder summoning[]

It was stated by Veldora that it took 30 mages and 30 days to summon an otherworlder. A contract is usually etched onto the soul of the summoned with the spiritual magic spell Locking Curse 「呪言, jugen」. It takes an enormous amount of magicules and could drain and kill the summoner if they are ill-prepared.
Miscellaneous & unknown[]
- Tempest Meteor 「爆覇流星嵐, tenpesuto mītia」: A technique of summoning magic that taps into dark magic to create meteors out of imaginary matter, which can then be summoned and rained upon targets. Under the effects of the laws of physics, the imaginary matter temporarily becomes real and capable of inflicting actual damage. However, because imaginary matter is magically produced, it can be countered by Magic Nullification.[2]
Trivia[]
- In The Martial Arts Tournament Rimuru accidentally refers Gobta's skill as Summoning Magic when guessing how Ranga got summoned.
References[]
- ↑ That Time I Got Reincarnated as a Slime light novel — Volume 8, Chapter 3
- ↑ That Time I Got Reincarnated as a Slime light novel — Volume 20, Chapter 3