Does an Ebonblade Reaper holding a Quietus Spike kill players?

Question

Ebonblade Reaper:

Whenever Ebonblade Reaper attacks, you lose half your life, rounded up. Whenever Ebonblade Reaper deals combat damage to a player, that player loses half his or her life, rounded up.

Quietus Spike:

Whenever equipped creature deals combat damage to a player, that player loses half his or her life, rounded up.

An Ebonblade Reaper hits a player while equipped with a Quietus Spike. Assuming no other effects, does the player lose the game?

My interpretation:

1. Ebonblade Reaper deals 1 combat damage to a player.
2. The Reaper and Quietus Spike triggered abilities are put onto the stack.
3. Each effect causes that player to lose half their life.
4. That player loses.

Answer 1

No, it doesn't work like that. The triggers decide how much damage to do when they resolve, not when they're put onto the stack.

So if your opponent were at 21 (to make things simple) it'd go like this:

• Ebonblade Reaper deals 1 damage, putting them at 20. Both triggers go on the stack.
• The first of the triggers resolves, making them lose 10 life, putting them at 10.
• The second of the triggers resolves, making them lose 5 life, putting them at 5.

You do get to pick what order the triggers go on the stack, but it doesn't really matter, since they're doing the same thing.

Answer 2

No

Each ability triggers and is put on the stack, then they resolve one at a time. Rule 608.2g describes one of the steps to follow when resolving a spell or ability:

608.2g If an effect requires information from the game (such as the number of creatures on the battlefield), the answer is determined only once, when the effect is applied.

In this case, both abilities refer to "his or her life". This value is checked when each ability resolves. The first ability will have finished resolving and therefore will have changed the player's life total before the second one begins resolving and checks it.

Answer 3

By expanding the scope of your question, you can achieve the desired result: winning.

If Ebonblade Reaper is given Double Strike, and it deals combat damage to your opponent during both combat damage steps, you will win if the opponent has 20 or less life.

During the first combat damage step (ref: 510.5 and 702.4), Ebonblade Reaper deals 1 damage to the opponent, triggering both effects. AS the controller of both effects, you choose the order in which they enter the stack (inconsequential).

The last in resolves, your opponent has T-1 = X life, and they lose Y life, where Y = ceiling (X/2). X'= X - Y. The second effect resolves, your opponent has X' life, and they lose Y' life, where Y'= ceiling (X'/2). X'' = X'-Y'

During the second combat damage step, Ebonblade Reaper deals 1 damage to the opponent.

The last in resolves, your opponent has X''-1 = M life, and they lose Y life, where Y = ceiling (X/2). M'= M - Y. The second effect resolves, your opponent has X' life, and they lose Y' life, where Y'= ceiling (X'/2). M'' = M'-Y'

Now, a table of numbers demonstrating the results, for starting opponent life totals of (0,21).

    T     X     X'    X''  M    M'   M''
    21    20    10    5    4    2    1  
    20    19    9     4    3    1    0  
    19    18    9     4    3    1    0  
    18    17    8     4    3    1    0  
    17    16    8     4    3    1    0  
    16    15    7     3    2    1    0  
    15    14    7     3    2    1    0  
    14    13    6     3    2    1    0  
    13    12    6     3    2    1    0  
    12    11    5     2    1    0    0  
    11    10    5     2    1    0    0  
    10    9     4     2    1    0    0  
    9     8     4     2    1    0    0  
    8     7     3     1    0    0    0  
    7     6     3     1    0    0    0  
    6     5     2     1    0    0    0  
    5     4     2     1    0    0    0  
    4     3     1     0   -1   -1   -1  
    3     2     1     0   -1   -1   -1  
    2     1     0     0   -1   -1   -1  
    1     0     0     0   -1   -1   -1  

Now, you may be wondering about the -1's at the bottom of the table. The applicable rule is 107.1b:

107.1b Most of the time, the Magic game uses only positive numbers and zero. You can’t choose a negative number, deal negative damage, gain negative life, and so on. However, it’s possible for a game value, such as a creature’s power, to be less than zero. If a calculation or comparison needs to use a negative value, it does so. If a calculation that would determine the result of an effect yields a negative number, zero is used instead, unless that effect sets a player’s life total to a specific value, doubles a player’s life total, sets a creature’s power or toughness to a specific value, or otherwise modifies a creature’s power or toughness.

In the event there is an effect that prevents your opponent from losing with due to having 0 or less life, the game continues.

After the Ebonblade Reaper deals damage during the second combat damage step, for starting life totals (1,4) your opponent is at -1 life. Calculating the effect, the ceiling of (-1/2) is 0.

It becomes interesting if the life total before the effect is applied is -2. Since the effect is determining how much life the opponent will lose, rather than setting the life total to a specific value, if it determines a negative value, the result is 0 instead.

For example, with -2 life, the opponent loses half their life, rounded up. (-2/2) = -1, rounded to -1. Rule 107.1b sees the negative value, and turns it into a 0.