The Seal is a powerful spell used to limit its target's immense power.
Part of her abilities that Iremi displayed and sealed were:
- She can read runes
- She can imitate magic by just seeing it once.
- She can craft completely new spells by just thinking of it - unlike the other spell users on the series, Iremi uses her own spells which she crafted herself while the others uses spells which they learned through study.
- She can cast a spell without ritual or incantation
- She is able to borrow nature's power - this abilty is what is to believe to be the most frightening because she can access the mana around her environment giving her an unlimited amount and access to mana.
She was also quoted to emit an enormous amount of aura even with the seal. And later on the series it was displayed that she was also able to use and tap to the other magical elements. A feat that is seemingly exclusive to their family line.
As what Edermask have hypothesize, the way that the seal work is that the more Iremi uses her ability to read runes the stronger the seal becomes. This is an effective method to hold back Iremi's power since she might be needing to read runes to strengthen her power which what the one who put the seal is trying to avoid. Wandra also masked Iremi's personality with another personality as an insurance that her formal personality will not cause so much trouble. Within time, this new pesonality melded with the former and became on what is now known as Iremi.
When Iremi falls unconscious during the fight with Shadow, a very powerful magician who shares Edermask's appearance, her true power is temporarily brought forth. Iremi, without the seal, is the only magician capable of using all the magical elements, and it is likely her ancestor was the same. Enzu judged Iremi's lightning attack during that one incident with shadow to be more powerful than Edermask's.
Iremi's seal is finally broken when she is on the verge of death while they're fighting against the ancient creature Cantera. In that condition she easily defeats the creature - something that all of the members of the group together with Edermask had failed to do.
"It's the angel of death that will drag you to hell."
-Iremi to the ancient monster
Janus states that Iremi might be an equal to Edermask, but apparently Cantera was stronger than Janus himself so he might be underestimating Iremi.
"You're really weak, aren't you?"
-Iremi to Edermask when the seal is broken
When her seal is finally broken it becomes clear that her personalities hadn't merged and the second personality wants to dispose of Edermask, Enzu and the whole group so that Iremi won't have any reason to try to come back. At the end the monks at the temple reseal her power and her second personality as well.
"Don't think you can lock me in forever!!! I'll remember this! I'll remember each and one of you! And one of this days I'll get all of you! I'll repay you hundredfold! "
-Iremi's second personality to the people that were sealing her
- The last time that the seal was placed was 12 generations prior to Iremi's (which is 200 years before the timeskip) on who is known to Edermask as "The Witch of the South" .