How is life gain applied?

[GameJayRemy]

When is life gain supposed to be applied when a monster has it?

Opponent was playing life gain via bats, and they had cavern bat on the field.
It was my turn and I push all my monsters to attack, he chooses his blockers.

I buff a creature he didn't block which lead my total damage to be enough to kill.
Their life hit 0 then 1 which them living through this turn meant I couldn't catch up anymore.


I've had a match in the past were the roles were reversed and I should have survived a turn via life gain with more or less the same cards they had out but it didn't tick at all once my health hit 0.

So a glitch clearly happened, but I'm not sure which part of it is the actual glitch.

Should the HP have ticked up before his Health hit 0 but it did it retroactively making this a visual bug?

Or was it not supposed to tick up until after his hp hit 0 killing them, making it a game play bug?

Order of operations with this sort of thing aren't something I am very familiar with, as I just started playing the game as of a few months ago and haven't played Magic in over 10 years.

[ʍolɟ ǝɥʇ ǝsɹǝʌǝɹ]

Its all applied during the combat phase. If it was a trigger it wouldn't have worked.

Its more so you can visualize what's happening and a design choice.

[Traumaturgy]

It checks after combat phase, so even when his health reached 0 during phase, game still had to resolve life gain from bats, so now he had more than 0 hp, fight ends and he was still alive. In combat all happens at the same time, but game just shows you the steps one by one, combat dmg is shown first and gain life second.

Something must have been different in second example, maybe your life was -1, bat increased to 0 and you died? Or maybe bat died earlier to some effect? Or maybe bat dealt no dmg so no gain life (it must deal dmg, so fog effect or -1/0 token will cause it to deal no dmg and no health gain).

[LunchBox]

combat happens simultaneously, so the life gain would be applied at the exact same time you got them to 0, meaning they would gain the life back. However if all of you creatures had first strike, then whoever has first strike or double strike applies their damage first before any other damage which means the life-gain wouldn't proc

[anaris]

This isn't about the order of combat operations actually. Losing the game because of life total is what's called a "state-based action" - there's a lot of nuances to it but essentially only when any current things have resolved do state-based actions get checked, they're rarely checked in the middle of a phase's activities (with the exception of the stack, which has state-based checks between each resolution iirc)