Metalripper

Battlerunner cannot attack colorless planeswalker permanents or players that control a colorless permanent.
At the beginning of each opponent's upkeep, if that player controls a colorless permanent, they lose 2 life.
When Karn arrived back on New Phyrexia, all of the Praetors took notice. But it was only those under the command of Urabrask who did not meet his wrath.