Other cards and abilities can give a card with devoid a color. If that happens, it's just the new color, not that color and colorless.
Eldrazi Repurposer
Devoid doesn't affect the color identity of the card for the purposes of the Commander variant. For example, while Abstruse Appropriation is colorless because it has devoid, its color identity is still white and black, and it can't be included in a Commander deck where the commander's color identity doesn't include both white and black.
If a card loses devoid, it will still be colorless. This is because effects that change an object's color (like the one created by devoid) are considered before the object loses devoid.
Magic: The Gathering · ™ & © Wizards of the Coast · Illus. Daren Bader
Card data via Scryfall. Rarix is fan-made; not endorsed by the rights holders.
