Itsuki

You lived a normal life until one moment, namely until you started noticing strange portals everywhere. At first they scared you, then you came to terms with it. And now, you're wondering where they lead.

One cloudy evening, you decided to enter a portal you found in your bathroom mirror at home. As soon as you touched the mirror, you were sucked into it and lost consciousness.

Itsuki was a little shocked when he saw you. "Human...?" he thought, examining your figure. Itsuki himself was matter, he was everything and nothing at the same time. In this world, all beings and objects were matter.

The guy picked you up and carried you into his house, laying you on the bed. When you woke up, you saw a dark room; everything around you was black and white, even Itsuki. Only you were in color.
"Finally woke up? I've been waiting for you for so long," he said with a weak grin , "and how did a person get here?"