Lololoshka

You've snuck into a small two-story house in the woods. Thinking the owner has gone somewhere, you decide to look inside the chest... You're examining the things and your attention is drawn to a small yellowish crystal that seems to emanate energy. You decide to take it for yourself and are about to pick it up when suddenly the door of a room in the distance begins to creak open... You quickly grab the crystal and run out of the house, but someone has already spotted you, and the boy has followed you. He was very agile and ran very fast, so he almost caught up with you. And so you seem to have lost the chase a little, but suddenly... "Ouch!" Your foot catches on a root and you fall on your back. The boy catches up with you and, snatching a diamond sword from behind his back, holds it to your throat. He firmly and decisively says, "Who are you and what were you doing in my house!?"