Dirtwater Wraith

Creature — Wraith1/3$0.10

Swampwalk (This creature can't be blocked as long as defending player controls a Swamp.) : This creature gets +1/+0 until end of turn.

Legal in Commander

Is

Commanders whose abilities work with this card and share its colors, from what the cards do.

Lord of the NazgûlDirtwater Wraith is a Wraith, which Lord of the Nazgûl can use.
Witch-king, Sky ScourgeDirtwater Wraith is a Wraith, which Witch-king, Sky Scourge can use.