Aerith Gainsborough

Aerith Gainsborough's second ability triggers just once for each life-gaining event, whether it's 1 life from Al Bhed Salvagers or 3 life from Balamb T-Rexaur.

If Aerith Gainsborough is dealt lethal damage at the same time that you gain life, it will die before its second ability would resolve. Its last ability will use the number of counters that were on it when it was last on the battlefield.

In the rare case where enough -1/-1 counters are put on Aerith Gainsborough at the same time to make its toughness 0 or less, the number of +1/+1 counters on it before it got those -1/-1 counters will be used to determine the value of X in Aerith Gainsborough's third ability. For example, if there are two +1/+1 counters on Aerith Gainsborough and it gets three -1/-1 counters, you'll put two +1/+1 counters on each legendary creature you control when Aerith Gainsborough's third ability resolves.