ZanTec is a magic Runeword created by combining a Zan Rune of Ritual and a Tec Rune of Invocation.
How to Create ZanTec
You can create ZanTec by adding the magic Zan Rune of Ritual and the magic Tec Rune of Invocation to a two-socketed 
Helm, 
Chest Armor, 
Pants, or 
Two-Handed Weapon.
Overflow
When ZanTec overflows, you receive the Tec Rune's overflow effect (Increased Size) 0.5 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