My take 02: Frodo and Sam.
Lord of the rings series by Sir J.J.R Toelkin is a master-epic and every character in it are larger than life, and in this records of heroism comes a humble tale of two hobbits- Frodo Baggins and Samwise Gamgee.
Bond by fate, co-incidences, faith, trust, love, promises and hardship, both these friends sketch a beautiful portrait of comradeship, faith and determination, which takes the definition of friendship to greater heights. I love these duo for the fact that they go through hell, yet in the end they remain as angelic as ever, but it's the way Sam remains by Frodo's side throughout that truly wins our heart.
He never once hesitated to stand by Frodo even at the face of death, and never once retraced his path come what may. It was his liveliness and positivity that helps Frodo emerge through the adversity and if anything, Sam is the heart of their story if Frodo is the life.