Gives you a X% chance to gain the Focused Casting effect that lasts for 6 sec after being the victim of a melee or ranged critical strike. The Focused Casting effect prevents you from losing casting time when taking damage while casting Priest spells and decreases duration of Interrupt effects by Y%.
Martyrdom is a priest talent which provides spell pushback and interrupt resistance upon receipt of a critical strike.
This talent is extremely useful in PvP, where melee classes will often land strings of hits. The Focused Casting effect allows you to continue to cast through these hits, and reduce the duration of interrupts as well.
Due to the built in resilience system occasionally counting non-critical hits as critical hits, Focused Casting sometimes does not proc on critical strikes. This system also prevents Focused Casting, Blessed Resilience, and Blessed Recovery from proccing from the same attack the majority of the time.