UrQua is a rare Runeword created by combining a Ur Rune of Ritual and a Qua Rune of Invocation.
How to Create UrQua
You can create UrQua by adding the magic Ur Rune of Ritual and the rare Qua Rune of Invocation to a two-socketed Helm, Chest Armor, Pants, or Two-Handed Weapon.
Ur - Your Minion or Companion kills an enemy or dies. (10)
Qua - Restore an Evade charge and gain 6% Movement Speed for 5 seconds, up to [6*5]%. (400)
Overflow
UrQua can not overflow because the amount of Offering you receive from the Ur Rune exactly fills the required Offering of the Qua Rune.
Overflow occurs when your Ritual generates more Offering than required for the Invocation. The overflow effect is proportional to the amount Offering overflows.