DeathtouchDeathtouch is a static ability.
A creature with toughness greater than 0 that’s been dealt damage by a source with deathtouch since the last time state-based actions were checked is destroyed as a state-based action. See rule 704.
Any nonzero amount of combat damage assigned to a creature by a source with deathtouch is considered to be lethal damage for the purposes of determining if excess damage is being dealt.
The deathtouch rules function no matter what zone an object with deathtouch deals damage from.
If an object is no longer in the zone it’s expected to be in as an effect causes it to deal damage, its last known information is used to determine whether it had deathtouch.
Multiple instances of deathtouch on the same object are redundant. (CR 702.2)
When Soul Drainer
enters the battlefieldShort for entering the battlefield. (CR 700.15),
destroyThe only ways a permanent can be destroyed are as a result of an effect that uses the word “destroy” or as a result of the state-based actions that check for lethal damage (see rule 704.5g) or damage from a source with deathtouch (see rule 704.5h). If a permanent is put into its owner’s graveyard for any other reason, it hasn’t been “destroyed.”
A regeneration effect replaces a destruction event. See rule 701.19, “Regenerate.” (CR 701.8) target
commanderA designated card for a Commander deck, governed by the command-zone, color-identity, and Commander rules. (CR 903) an opponent controls. Remove all
commander damageA player dealt 21 or more combat damage by the same commander over a game loses. (CR 903.10) that
commanderA designated card for a Commander deck, governed by the command-zone, color-identity, and Commander rules. (CR 903) dealt to you. (You don't gain life, just treat it as though your
commander damageA player dealt 21 or more combat damage by the same commander over a game loses. (CR 903.10) from that
commanderA designated card for a Commander deck, governed by the command-zone, color-identity, and Commander rules. (CR 903) is zero.)