At the beginning of each opponent's end step, if you didn't lose life this turn, you may put a quest counter on Luminarch Ascension. (Damage causes loss of life.)
: Put a 4/4 white Angel creature token with flying onto the battlefield. Activate this ability only if Luminarch Ascension has four or more quest counters on it.
10/1/2009 Luminarch Ascension's first ability has an "intervening 'if' clause." It checks whether you've lost life during the turn both as it would trigger and as it resolves.
10/1/2009 Life lost during the end step after Luminarch Ascension's first ability resolves has no bearing on it.
10/1/2009 Luminarch Ascension's first ability checks only whether life was lost. It doesn't care whether life was also gained. For example, if you lost 4 life and gained 6 life during the turn, you'll have a higher life total than you started the turn with -- but Luminarch Ascension's first ability won't trigger.
10/1/2009 Luminarch Ascension's second ability checks how many quest counters are on it only at the time you activate the ability. Once activated, the ability will resolve as normal even if quest counters are removed from Luminarch Ascension.
10/1/2009 In a Two-Headed Giant game, Luminarch Ascension's first ability will trigger twice at the beginning of the opposing team's end step if you didn't lose life that turn. If both abilities resolve, it will get two quest counters. (It doesn't matter whether your teammate lost life or not.)