Lone Revenant
Creature — Spirit
Hexproof (This creature can't be the target of spells or abilities your opponents control.)
Whenever Lone Revenant deals combat damage to a player, if you control no other creatures, look at the top four cards of your library. Put one of them into your hand and the rest on the bottom of your library in any order.
Illustrated by
Commander 2015#96RareEnglishLegality
Rulings
You must put one of the cards into your hand, even if you’d rather put all four on the bottom of your library.
If you control Lone Revenant and any other creature (including another Lone Revenant), its ability won’t trigger.
Check whether Lone Revenant’s ability triggers after combat damage is dealt but before any creatures that are destroyed due to combat damage leave the battlefield. For example, if you control Lone Revenant and another creature, and that other creature takes lethal damage in the same combat damage step that Lone Revenant deals damage to a player, Lone Revenant’s ability won’t trigger.
If you control no creatures when Lone Revenant’s ability resolves, you’ll still look at the top four cards and put one into your hand.