How would you get rid of an emblem like the one {Domri Rade} has?
Currently there is no way to interact with emblems except by starting a new game. Wether you win, lose, or restart it with {Karn liberated}
Nothing can interact with Emblems, because no card references them or the command zone, and they are not card types - so presumably nothing ever could reference them. Emblems also have no characteristics, so nothing can alter what they do.
113. Emblems
113.1. Some effects put emblems into the command zone. An emblem is a marker used to represent an object that has one or more abilities, but no other characteristics.
113.2. An effect that creates an emblem is written "[Player] gets an emblem with [ability]." This means that [player] puts an emblem with [ability] into the command zone. The emblem is both owned and controlled by that player.
113.3. An emblem has no characteristics other than the abilities defined by the effect that created it. In particular, an emblem has no name, no types, no mana cost, no color, and no expansion symbol.
113.4. Abilities of emblems function in the command zone.
113.5. An emblem is neither a card nor a permanent. Emblem isn't a card type.