Hiccup and Toothless's Relationship

Hiccup found toothless by shooting him down in the woods. He decided not to kill him because he looked at him and saw himself. They became best friends, and they are best friends for the whole series. The relationship they have is a brotherly relationship. Valka revealed in the 2nd movie that toothless was hiccups age and thats why they get along with each other so well.