KaaLum is a rare Runeword created by combining a Kaa Rune of Ritual and a Lum Rune of Invocation.
How to Create KaaLum
You can create KaaLum by adding the rare Kaa Rune of Ritual and the magic Lum Rune of Invocation to a two-socketed 
Helm, 
Chest Armor, 
Pants, or 
Two-Handed Weapon.
Overflow
When KaaLum overflows, you receive the Lum Rune's overflow effect (Increased Resource Restored) 9 times.
Overflow occurs when your Ritual generates more Offering than required for the Invocation. The overflow effect is proportional to the amount Offering overflows.
Legions
Helltide