If I activate a relic, which has crit chance on it, and, at the end of it's 20 second duration, I am in the middle of an ability, is the chance of the ability to crit taken from when the ability was started(during which crit chance was higher) or from when it ends(when crit chance returns to it's normal amount)?
After a few runs (103 to be precise), damage is applied on the tick that it happens. Meaning that for cast time abilities the damage applies after the cast time and is recalculated on every tick. It appears that if the relic is active for any part of the tick than it is applied to the entire tick so the optimum time to pop the relic/ability is the time between ticks as you get two extra ticks out of the relic. Sadly, this means that if you have a cast time of four secs with three secs left on the relic, you see no benefit and should pop a different ability.