YulVex is a legendary Runeword created by combining a Yul Rune of Ritual and a Vex Rune of Invocation.
How to Create YulVex
You can create YulVex by adding the legendary Yul Rune of Ritual and the legendary Vex Rune of Invocation to a two-socketed Helm, Chest Armor, Pants, or Two-Handed Weapon.
Yul - Cast a Skill with a Cooldown. (50)
Vex - Gain +3 to all Skills for 8 seconds. (1000)
Overflow
YulVex can not overflow because the amount of Offering you receive from the Yul Rune exactly fills the required Offering of the Vex Rune.
Overflow occurs when your Ritual generates more Offering than required for the Invocation. The overflow effect is proportional to the amount Offering overflows.