Undo
"The hero Ys Aika's most prided spell. Undo allows one to revert to a previous state of existence – in both time and space."
Upon use, the player will retrace the movements they made in the last few seconds. This doesn't affect the surroundings, only the player.
If the player dies while this spell is equipped in any of the 4 spell slots, and has at least 1 available charge, then the spell will automatically trigger, even if the player has no energy. After the player is revived, the player will lose all of their remaining energy, the spell will lose all of it's charges, and the maximum amount of charges will be reduced by 1. If the spell has 0 maximum charges after this, then the spell is unlearned.
Because the spell doesn't affect the player's surroundings, sometimes the player can be warped into a bad situation. For example, if the player falls into lava, jumps out of the lava, then burns to death, 'Undo' would trigger, and would warp the player back into the lava to die a second time.
During the tutorial, 'Undo' will always trigger upon death despite not being a learned spell.