Somemone in my playgroup is sending a e-mail ramble around about Consequences of Negative Life Totals.
>>> Does Magic Use or allow negative life totals?
The e-mail ramble follows:
Consequences of Negative Life Totals:
You control Death's Shadow.
This is a case where we make a calculation whose result modifies power or toughness of a creature; in such a case, negative numbers are used.
If you are at 5, Death's Shadow gets -5/-5; if you are at -5, Death's Shadow gets -(-5)/-(-5) =
An effect doubles your life points (for example Beacon of Immortality).
This is a case where we make a calculation whose result sets life totals; in such a case, negative numbers are used.
If you are at 5, you will end at 10; if you are at -5, you will end at -10. Please note that here you are gaining life (5 gained life points in the first example) or losing life (5 lost life in the second example); any triggered ability that triggers whenever you gain/lose life will trigger.
If you are at -5, you won’t be able to cast Deep Analysis using its flashback ability, (“pay 3 life”), and you won’t be able to exile cards with Necropotence.
Finally, let’s take a look at a tournament situation.
Player A is at 6 life points and controls Abyssal Persecutor; Player B is at -10. B attacks with two 6/6 creatures, A blocks with the Abyssal Persecutor (which will be destroyed). It looks like A goes to zero life points (and dies) and the Abyssal Persecutor dies (so making B die too) at the same time, but it works differently.
When combat damage resolves, the Persecutor is a 6/6 with 6 damage on it, and player A goes to zero life points; then, when state based actions are checked, two things happen:
The Abyssal Persecutor is destroyed
A loses the game
Note that B would lose the game (because he has -10 life points) when state based actions would be checked *again*; it’s not simultaneous. The final result is that B wins the game.