K here you go cuz i dont got time to type down the whole triggger ill say this nice and fast.
[1] When her dies make corpse where unit died named what the dieing hero was add teem glow.
[2] Set a spell for the corpse, DUMMY SPELL like smash ground and make to deal "o damage"
[3] Make it when you cast spell on body or near "% of area - like 300" will revive last killed hero where that corpse is.
[4] When hero is summoned back make it so the corpse goes away.
Sorry this is all i can give you, Mind my bad english im not from USA or AUS