Simple question, yet unclear to me:
Someone attacks with a spirit creature, let's say a 2/2. I block with lets say two creatures, each 1/1.
Then the attacker plays Essence Flux, removed his attacker from the game to return it as a 2/2 mi a +1/+1 counter on it.
When the creature returns to the battlefield it has no memory of anything that happened earlier in the game. This means that it is no longer attacking, and thus is no longer being blocked by the defending player's creatures. This also means that it will neither deal nor receive combat damage, so neither it nor the defender's creatures will die.
400.7. An object that moves from one zone to another becomes a new object with no memory of, or relation to, its previous existence. There are nine exceptions to this rule: [none of the exceptions apply to this case]
When the creature returns to the battlefield, it's a brand new creature unrelated to the one that used to be on the battlefield.
400.7. An object that moves from one zone to another becomes a new object with no memory of, or relation to, its previous existence. There are nine exceptions to this rule: [None of the exceptions apply]
This new creature isn't attacking and isn't being blocked because it never attacked. It's not in combat at all. As such, no creatures deals any combat damage.
