YulZec is a legendary Runeword created by combining a Yul Rune of Ritual and a Zec Rune of Invocation.
How to Create YulZec
You can create YulZec by adding the legendary Yul Rune of Ritual and the rare Zec Rune of Invocation to a two-socketed Helm, Chest Armor, Pants, or Two-Handed Weapon.
Yul - Cast a Skill with a Cooldown. (50)
Zec - Reduce your active Ultimate Cooldown by 4 seconds. (200)
Overflow
YulZec can not overflow because the amount of Offering you receive from the Yul Rune exactly fills the required Offering of the Zec Rune.
Overflow occurs when your Ritual generates more Offering than required for the Invocation. The overflow effect is proportional to the amount Offering overflows.