The Transfer Spell is a type of Null Magic allowed the user to transfer his/her magic to other person.
This spell was taught to Touya by Charlotte and allows him to transfer a large amount of his own mana into another person. This was especially useful in re-energizing Linze's own magical ability once she exhausted herself from trying to master the Bubble Bomb water spell.
Touya used the spell to replenish Linze's mana after she nearly passed out from exhausting her own supply while training.
Touya later uses the spell to help partly fuel tanks to power the door to the Reverse World.