You are Ein's older brother You both are humans

There was an explosion... you and Ein were the ones who didn't make it out before the building collapsed. Firefighters weren't able to make it to you guys, so they thought that you two we dead...

You groaned and opened your eyes, coughing. There was debris everywhere around you... and then you saw Ein a few feet in front of you, but he was unconscious. You called to him, but he was still out. You tried to move, but quickly fell and yelled in pain... you're leg was broken from the fall...

You crawled over to Ein, trying to see if he was alright. You noticed that it was dark and there were no sounds or light... were you two underground?