Lone Revenant — ruling 1

You must put one of the cards into your hand, even if you’d rather put all four on the bottom of your library.

Lone Revenant — ruling 2

If you control Lone Revenant and any other creature (including another Lone Revenant), its ability won’t trigger.

Lone Revenant — ruling 3

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.

Lone Revenant — ruling 4

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.

Lone Revenant : règles, fonctionnement et interactions (MTG)

Lone Revenant is one of those cards players keep asking about. Here is, in plain words, what its official text says, the rulings published by Wizards of the Coast, and the combos players actually run.

Official card text

Hexproof (This creature can't be the target of spells or abilities your opponents control.) Whenever this creature 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.

How it works : Lone Revenant

Original English text — Wizards of the Coast / Scryfall

#1May 1, 2012· Wizards of the Coast
You must put one of the cards into your hand, even if you’d rather put all four on the bottom of your library.
No other card is named in this ruling.
#2May 1, 2012· Wizards of the Coast
If you control Lone Revenant and any other creature (including another Lone Revenant), its ability won’t trigger.
No other card is named in this ruling.
#3May 1, 2012· Wizards of the Coast
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.
No other card is named in this ruling.
#4May 1, 2012· Wizards of the Coast
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.
No other card is named in this ruling.