Forum:Help with Gorz the Emissary of Darkness

Some help with this card i can't find in rullings if i can summon Gorz the Emissary of Darkness under this conditions:

1.Gorz is the only card in my hand and i get attacked by Spirit Reaper.I have to discard Gorz or i can sumon it?

2.If i control a monster with 1900 attack and is the only card on my field.Then my opponent attacks with a monster of 2000 atack. Can i summon Gorz when i get 100 damage and my monster is destroyed by the attack?