Awaken is the most important thing to power up a character. Once the character reaches its max level, it can be awakened to increase the star level and stats. Additionally, some of the characters acquire secret techniques, which are special moves requiring more chakra than Ninjutsu, as being awakened.
What are needed to awaken?
Awakening materials
Awakening requires specific awakening materials by characters. For example, Naruto Uzumaki ( The Worst Loser ) at star level 3 needs Awakening scrolls ( Heart Book ) to be awakened.
Ryo
It also costs Ryo, which was a currency of Japan in the past. A player can earn Ryo by succeeding missions and as reward for deceiving conditions during missions.
Im having trouble awakening the "Zabuza the demon returns" hes max level and it wont even allow me to awaken to 6 star. Not even review the requirements
I have a 4 star sasuke on max level but ibdont have the option to awaken him to 5star, I also have a kakashi and itachi on max level, but it's not showing max level just shows level 70
You can awaken a character only once. If the character was initially bronze it can be awakened to silver and similarly from silver to gold and from gold to blue. If the character was initially bronze you cannot awaken it to gold.
Your Sasuke is not capable of becoming a 5-star, and the I'm guessing it says level 70 rather than max is because it's possible to limit-break it, increasing the amount of levels of your character from a max of 70 to 75, and so on and so forth.