Master of Cruelties is a 1/4 with first strike and deathtouch. If I were to attack with Master of Cruelties and he gets blocked by a creature with 4 or more power, would Master of Cruelties die or would the first strike and deathtouch combo cause the other creature to die before Master of Cruelties is dealt damage?
Generally speaking, the Master will survive the battle; the first strike/deathtouch combo is that powerful (but appropriate for a 5 mana multicolor card). First strike will make sure the Master deals combat before creatures without this ability; with deathtouch, even a single damage is enough to kill a creature. In the 'regular' combat damage step, when the blocker would deal damage, it's already dead.
Some exceptions are when the blocker has first strike as well (or double strike), or when it has protection from black or from red. In the first case both creatures die, in the second case only the Master.
Master of Cruelties will typically kill any single creature that blocks it before the blocking creature can deal damage back. This is because first strike causes Master of Cruelties to deal damage first, and deathtouch causes any damage dealt by Master of Cruelties to be lethal. If a creature without first strike or double strike dies during the first strike combat damage step, it doesn't deal damage during combat damage step.
The relevant rules are the following:
702.7b If at least one attacking or blocking creature has first strike or double strike (see rule 702.4) as the combat damage step begins, the only creatures that assign combat damage in that step are those with first strike or double strike. After that step, instead of proceeding to the end of combat step, the phase gets a second combat damage step. The only creatures that assign combat damage in that step are the remaining attackers and blockers that had neither first strike nor double strike as the first combat damage step began, as well as the remaining attackers and blockers that currently have double strike.
702.2b 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.
There are a number of ways that this can be foiled however. Here are some examples:
If the blocking creature has first strike or double strike, the creatures will deal damage simultaneously.
If the blocking creature doesn't take damage, such as from protection (Mother of Runes), damage redirection (Harm's Way), or damage prevention (Healing Salve), deathtouch doesn't apply because the blocker hasn't taken damage.
If the blocking creature has indestructible, it is not destroyed by lethal damage (including damage from deathtouch) and will deal damage to Master of Cruelties. (Note that regeneration will save a creature from dying but will not allow it to subsequently deal damage in this case because Master of Cruelties is dealing damage first and regenerating removes the creature from combat).
If multiple creatures block Master of Cruelties and Master of Cruelties power is still 1, Master of Cruelties can only kill one of them. The other(s) will survive to deal damage to him.
If an effect reduces Master of Cruelties's power to less that 1 (Cower in Fear, Serrated Arrows, Night of Souls' Betrayal, etc), Master of Cruelties can't kill anything in combat because he needs to deal any damage for deathtouch to work.
Generally Master of Cruelties(Master) will survive any block like that, but there are exceptions, it all depends on the creature that is blocking Master. The cases where he dies are (Assuming the blocker has enough power or also has deathtouch):
- The blocker also has First Strike, or has Double Strike - Since both creatures do damage in the first combat damage step, they both take damage. In this scenario both die.
- The blocker is indestructible - Since the blocker is indestructible Master can't kill it. The damage will be done during the first damage step, indestructible prevents the effect of deathtouch, the blocker won't die and will hit back during the second damage step. Even if the creature loses indestructible (Burn from Within) after the damage is dealt, this will not kill it, deathtouch only works as the damage is dealt.
- The blocker has protection from one of Master's characteristics - If the blocker has protection, Master can't do damage to it, without damage deathtouch does nothing and the blocker has the chance to hit back. Currently protections that would work are: Black, Red, Multicolored(Enemy of the Guildpact), All Colors(Iridescent Angel), Creatures(Beloved Chaplain), Mana Cost(Mistmeadow Skulk), Player (True-Name Nemesis) and Everything (Progenitus)
- There are multiple blockers - Master is a 1/4 creature, for deathtouch to work he needs to do 1 damage to each creature in the block, If he is blocked by two 4/4 creatures he will kill one, but the other will get the chance to hit and kill him.
- Master cannot do damage or the blocker cannot take damage - There are effects that prevent creatures from doing damage Fog, or prevent them from taking damage, like Protean Hydra. Some of these effects are very targeted, preventing damage to or by a specific creature (Heart of Light), by creature type (Moonmist), or by opponent's creatures(Winds of Qal Sisma), that would let the blocking creature still hit Master back.
- Master has no power - There are ways to reduce a creature's power, either for the turn or in the form of -1/-1 counters. If Master has no power when he hits, no damage is dealt.
- Damage is redirected - If the damage is redirected(Harm's Way) that Master would do, it is never dealt to the blocker, this means the blocker is still there in the second combat damage step. The damage still is done by Master so it still has deathtouch when it is dealt to whatever it is redirected onto, possibly even Master himself.
- Some other effect destroys master - Engulfing Slagwurm for instance destroys everything it blocks, before any damage is dealt either way, in this case Master never reaches the first combat damage step.