I am attacking with my only creature, Dragon-Style Twins, a creature with 3 power and Double Strike.
My opponent is blocking with two Griffin Sentinel, which have 3 toughness.
After he declares both Sentinels as blockers, he flashes in Dictate of Erebos, which says
Whenever a creature you control dies, each opponent sacrifices a creature.
How does Dragon-Style Twins's double strike work against the Sentinels? Is Dictate of Erebos triggered after the first combat damage phase, which would require me to sacrifice my Twins before I can deal damage to the second one?