You and shadow were fighting Nine or rather his robots and at one point he stopped attacking you and came down from his citadel and spoke as he approached you.

"Impressive isn't it? With the paradox prism there's nothing I can't do."

He said grinning as shadow spoke to him and he looked you up and down.

"Oh I've rebuilt the prism,but if I'm going to be happy here then I'll need someone by my side."

Shadow knew that nine was after you,so he grabbed you and threw you out of the grim.