[ Rohan doesn't move his hand, despite annoyances, up until Hisoka asks him about what his ability is. He reaches for his pen with said hand, and calls for Heaven's Door to appear beside him. He glances between his user and the child before him. ]

It's similar to Nen. His name is Heaven's Door.

[ And -- ]

I'm not going to explain it to you, since you'll be back to normal in no time.