During a catastrophic breach between Universe 6 and Universe 10 (caused by a rogue Fu experiment), Android 18 accidentally absorbs inter-dimensional rift energy. Her infinite energy reactor, instead of overloading, syncs with the flow of timelines. Suddenly, she can see every version of herself:
Ultima Shenron’s eyes glowed with a terrifying, pale light. "A life for a life across the dimensions. To anchor her here, another must be cast out. This is the Interdimensional Law." dragon ball interdimentional wish android 18 u upd
She looked at Krillin one last time, memorizing the scars on his face, the shape of his nose, the way he looked at her like she was the only person in the world. Dragon Ball Interdimensional Wish: Android 18 "U Upd"
The girl instantly solidified, falling into Krillin’s arms, breathing deeply. But as the light faded, 18 collapsed. Her skin now had a faint, metallic sheen, and her eyes, once vibrant blue, were now glowing LED optics. She was no longer a cyborg; she was a total machine—a pure Android 18 from an alternate, darker timeline where the Red Ribbon Army had never fallen. Goku hesitates