Jack 1.0
Simply watching as Jack prepares defensive magic, she continues to exegete the plot device, "You won't be so lucky as to stay dead, unlike me.
"This portal bubble is in the void between your universe and my own. When I cease powering the spell, this bubble will pop, instantaneously saturating you with Magus particles and void-stuff.
From then on, whenever you die, you'll find yourself alive in a different universe. No guarantees you'll be able to survive there. You'll get to keep most of your stuff.
I know all of this, because the man who murdered nearly half of the people in my universe is named Jack, the immortal King, and he looks, sounds and even feels just like you. I was one of his wives. After your first death, the last part of my spell will pull you into my universe. You're on your own, now. Make your life count, you only have one life to live." She winks, then she winks out, immediately followed by the bubble's edge as it shrinks at the speed of light, imploding everything within into the quiet chaos of the void. Jack's nerve cells didn't even have time to inform him of their pressurized demise before his brain was gone too.