2013-09-15 : Heroic abilities will resolve before the spell that caused them to trigger.

2013-09-15 : Heroic abilities will trigger only once per spell, even if that spell targets the creature with the heroic ability multiple times.

2013-09-15 : Heroic abilities won’t trigger when a copy of a spell is created on the stack or when a spell’s targets are changed to include a creature with a heroic ability.

2018-12-07 : The amount to pay for {X} is chosen as the triggered ability resolves. No player may take actions between the time you pay {X} and the time Hero of Leina Tower has X +1/+1 counters on it.