i have two objects i want one of this object to kill another object thats okay but after that end the game
You must have the character somewhere in the game (can be opacity 0 or can be outside of screen). In the Death Animation box of the 2 objects you spawn an enemy that will kill the character
If you already had a character in the game that's even better. Just put an enemy in the death animation of the 2 objects and make it big enough that it will kill your character and that's it