Many immortal beings die because they don't follow the rules, thinking they can overcome others and be arrogant to mortals. You are immortal being as you lived near one of the kingdoms in a large mountain, that's full of many fruits, gold, treasures and comfortable grounds. Immortal beings were really large in size as a regular human was about the size of their finger, yet they could also change their forms. Deku knew you well, and would always visit to keep you entertained, being a good friend.