Spirit Summoning is a rare magical ability which allows the user to call forth spirits to aid them.
Iremi is capable of using the Spirit of Sleep, Yenasnabuen to grow flowers that puts her opponents to sleep for at least half a day.
Borrowing the forest's natural strength,
I pray for the elements within this region,
One that robs the body of freedom, Kashimilhon.
One who puts all into a deep slumber, Yenasnabuen.
I call upon them.
I, Iremi, call upon the might of the forest...
I summon the elemental spirits that dwell within
Sillavionne with eminent strength.
Galaglenne, one who confines all.
From the dark chaos and shadows, Kartelluine.
Shining bright like a jewel, Yullnie.
Kallkadian of bewitchment.
Yenasnabuen, who puts all into deep slumber.
Nauctious, who guides growth and regeneration.
Kashimilhon, who steals all freedom.
Ennimoiseum of memories.
Answer my call.
Iremi summons two beautiful spirits, Kashimilhon and Yenasnabuen to immobilize her opponents and put them to sleep. She claims this as her best spell and it takes at least a minute to cast. In the Forest of Truth, she casts this easily because of all the mana swirling around. She has a very good relationship with the two spirits, and whenever she summons them they immediately shower her with affection and fight for her attention. Iremi, however finds this embarrassing and usually ends up yelling at them. Even so, she has absolute faith in their abilities and calls them her "kids". They automatically didn't like Edermask since during their first meeting he questioned why Iremi left her opponent alive, and later while they were speaking to Iremi he told her to bring him his coat to cover Matthew. They saw this as being beneath Iremi and threatened to teach Edermask a lesson.
After the timeskip it seems that Iremi has drastically increased the number of spirits she has contracts with. During the first battle against Lord Modern's soldiers, she summons nine spirits with a single spell to create a monstrous being capable of using all nine spirits powers easily. Iremi later brags that the being is not a lifeless doll or golem but that ever single piece of it is controlled by her manually, while for most normal magicians, controlling a few roots proves to be a difficult and intricate process.