Naruto Uzumaki and Sasuke Uchiha are one of the most iconic duos to exist in the world of anime. Both have seen a fair deal of hardships throughout their early life.
Naruto, an orphan from birth, was ostracized for being the jinchuriki of the Kyubi or the nine-tailed fox.
Everyone either hated or feared him due to which he was unable to make any friends and felt lonely while he was attending the ninja academy.
Sasuke Uchiha, on the other hand, was living a happy life until one night when his older brother Itachi Uchiha massacred their entire clan leaving Sasuke as the sole survivor of the incident.
Having witnessed the horrendous scene, Sasuke’s goal was to be powerful enough to defeat his older brother to exact his revenge.
Their early childhood paved way for different mindsets in both of them as genins.
Naruto wanted to grow stronger to be acknowledged by everyone whereas Sasuke wanted to grow stronger to kill Itachi as payback.
Both of them were very competitive with each other but shared the same feeling of protecting their comrades.
Both of them improved during the chunin exam arc and Konoha crush arc but eventually, Sasuke noticed the amount of progress his teammate made is huge compared to what he has made.
Sasuke went to Orochimaru to seek more power to accomplish the only goal he had in mind, to kill Itachi.
He looked for vengeance and vengeance alone while Naruto understood the situation which made Sasuke a spiteful person and tried his best to bring his friend back home.
Loss of loved ones
After killing Itachi and learning the actual truth, Sasuke falls into a well of hatred and resentment against the village and plans to destroy the Konoha village.
Naruto upon learning the news of Master Jiraiya’s death falls into a depression but quickly overcomes it to become the man his sensei would be proud of.
He understands that the answer to world peace might not be known to him but he will keep trying to find it and never give up on the ideals taught to him by Jiraiya sensei.
Just as Kiren said, Naruto’s chakra was as bright as the sun and it gave a feeling of warmth, a stark opposite to Sasuke’s chakra which was very dark and cold.
Naruto being the ever optimist liked to look at the bright side of things whereas Sasuke was the opposite and gave in to hate and resentment.
Sasuke’s yin nature represented darkness or the physical energy and Naruto’s yang energy scented light but both of them were required to kill Kaguya Otsutsuki.
This shows neither of the energies can co-exist without one other.
It would be wrong to be at either end of the spectrum since humans have both light and darkness within them and a balance between them would help to defeat any powerful enemy in the same way Naruto and Sasuke defeated Kaguya.
Thanks for reading!