Vampire Warlord — ruling 1

Activating Vampire Warlord’s ability causes a “regeneration shield” to be created for it. The next time that creature would be destroyed that turn, the regeneration shield is used up instead. This works only if the creature is dealt lethal damage, dealt damage from a source with deathtouch, or affected by a spell or ability that says to “destroy” it. Other effects that cause the creature to be put into the graveyard (such as reducing its toughness to 0 or sacrificing it) don’t destroy it, so regeneration won’t save it. If the regeneration shield isn’t used, it goes away as the turn ends.

Vampire Warlord — ruling 2

To work, the regeneration shield must be created before Vampire Warlord is destroyed. This usually means activating its ability during the declare blockers step, or in response to a spell or ability that would destroy it.

Vampire Warlord — ruling 3

If Vampire Warlord is dealt lethal damage and is dealt damage by a source with deathtouch during the same combat damage step, a single regeneration shield will save it.

Vampire Warlord : règles, fonctionnement et interactions (MTG)

Vampire Warlord 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

Sacrifice another creature: Regenerate this creature. (The next time this creature would be destroyed this turn, instead tap it, remove it from combat, and heal all damage on it.)

How it works : Vampire Warlord

Original English text — Wizards of the Coast / Scryfall

#1July 1, 2013· Wizards of the Coast
Activating Vampire Warlord’s ability causes a “regeneration shield” to be created for it. The next time that creature would be destroyed that turn, the regeneration shield is used up instead. This works only if the creature is dealt lethal damage, dealt damage from a source with deathtouch, or affected by a spell or ability that says to “destroy” it. Other effects that cause the creature to be put into the graveyard (such as reducing its toughness to 0 or sacrificing it) don’t destroy it, so regeneration won’t save it. If the regeneration shield isn’t used, it goes away as the turn ends.
No other card is named in this ruling.
#2July 1, 2013· Wizards of the Coast
To work, the regeneration shield must be created before Vampire Warlord is destroyed. This usually means activating its ability during the declare blockers step, or in response to a spell or ability that would destroy it.
No other card is named in this ruling.
#3July 1, 2013· Wizards of the Coast
If Vampire Warlord is dealt lethal damage and is dealt damage by a source with deathtouch during the same combat damage step, a single regeneration shield will save it.
No other card is named in this ruling.