This is the rarest mana in the game. Ice mana exists only in the unique feature Letum Frigus, which might not be placed in game normally. The only other way to get it is to have the Illians palace. The spells it allows is Slow, Summon Ice elemental, and Blizzard. Slow removes the Haste promotion and reduces the movment of a unit by one to a minimum of one. Summon Ice elemental requires channeling 2 and creates an Ice elemental for 1 turn, two if you have the summoner trait. Blizzard can only be cast with channeling 3 and does 20-80% damage to any unit and turns all tiles within one radius of the caster to ice for a while.