Propagator Drone

Devoid works in all zones, not just on the battlefield.

Multiple instances of evolve trigger separately and, similar to above, the stat comparison takes place for each one independently as they try to resolve.

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.

Whenever a creature enters the battlefield under your control, check its power and toughness against the power and toughness of the creature with evolve. If neither stat of the new creature is greater, evolve won't trigger at all.

If a creature enters the battlefield with +1/+1 counters on it, consider those counters when determining if evolve will trigger. For example, a 1/1 creature that enters the battlefield with two +1/+1 counters on it will cause the evolve ability of a 2/2 creature to trigger.

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.

When comparing the stats of the two creatures for evolve, you always compare power to power and toughness to toughness.

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.

A card with devoid is just colorless. It's not colorless and the colors of mana in its mana cost.