UrNer is a rare Runeword created by combining a Ur Rune of Ritual and a Ner Rune of Invocation.
How to Create UrNer
You can create UrNer by adding the magic Ur Rune of Ritual and the rare Ner 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)
Ner - Invoke the Rogue's for 5 seconds, gaining Dodge Chance, Movement Speed, Unstoppable, and Stealth. (600)
Countering Concealment
Overflow
UrNer can not overflow because the amount of Offering you receive from the Ur Rune exactly fills the required Offering of the Ner Rune.
Overflow occurs when your Ritual generates more Offering than required for the Invocation. The overflow effect is proportional to the amount Offering overflows.