Raven's Run

Damage from creatures with wither affects players and planeswalkers normally.

If an ability of a plane refers to "you," it's referring to whoever the plane's controller is at the time, not to the player that started the game with that plane card in their deck. Many abilities of plane cards affect all players, while many others affect only the planar controller, so read each ability carefully.

You must target three different creatures when the chaos ability triggers, even if that means you have to target creatures you control. If you can't target three creatures (because there are just two creatures on the battlefield, perhaps), the ability is removed from the stack and does nothing.

The -1/-1 counters that result from wither remain on the damaged creature indefinitely. They won't be removed if the creature regenerates or the turn ends.

A face-up plane card that's turned face down becomes a new object with no relation to its previous existence. In particular, it loses all counters it may have had.

If the source of the damage is still on the battlefield at the time that damage is dealt, its characteristics are checked to see if it has wither. If the source has left the battlefield by then, its last existence on the battlefield is checked to see if it had wither.