Whenever one or more Rogues you control deal combat damage to a player, that player mills a card for each 1 damage dealt to them. If the player mills at least one creature card this way, you draw a card. (To mill a card, a player puts the top card of their library into their graveyard.)
Because damage remains marked on a creature until the damage is removed as the turn ends, nonlethal damage dealt to other Rogues you control may become lethal if Anowon leaves the battlefield during that turn.
2020-09-25 • wotc
The player dealt combat damage mills cards only for the damage dealt by your Rogues, not for any other combat damage dealt to them at the same time.
2020-09-25 • wotc
You draw just one card, no matter how many creature cards the player mills beyond the first.
2020-09-25 • wotc
If Rogues you control deal combat damage to two players at once, Anowon’s ability triggers twice.