LithThul is a legendary Runeword created by combining a Lith Rune of Ritual and a Thul Rune of Invocation.
How to Create LithThul
You can create LithThul by adding the legendary Lith Rune of Ritual and the rare Thul Rune of Invocation to a two-socketed Helm, Chest Armor, Pants, or Two-Handed Weapon.
Lith - Stand still while fighting for 0.31 seconds. (25)
Thul - Invoke the Sorcerer's , inflicting Freeze and Vulnerable onto enemies. (400)
Mystical Frost Nova
Overflow
LithThul can not overflow because the amount of Offering you receive from the Lith Rune exactly fills the required Offering of the Thul Rune.
Overflow occurs when your Ritual generates more Offering than required for the Invocation. The overflow effect is proportional to the amount Offering overflows.