Haste

In the game: help slow

Slow an enemy, or haste yourself.

Syntax: cast haste [target]
Syntax: cast slow <target>

Slow lowers your enemy's speed. With the Alternate rune (til) it becomes Haste, which raises your speed so you move and attack faster.

Haste and Slow do not stack: casting either fails on someone who already has one of them.

The game also finds it under: slow, haste.