This manga had everyone born with an animal spirit. Those who get strong ones become important and powerful. The main character get a "boring" cat and goes to a school to train the guardians. Turns out his cat was a legendary tiger hiding.
1 Answer
Is this the WEBTOON Flow? (Now available as a Daily Pass series, that is, wait to read for free.)
The wiki explains:
Yun Lee-Rang is a young man with a cat anima. After being beat up and put into the hospital his cat anima is revealed to be one of the strongest animas in disguise; the White Tiger. The White Tiger anima allows him to cast a wish and he uses it to turn back time. He soon repeats the cycle of his day but several consequences were found with turning back time.
At the school, everyone uses their animal-based powers to fight, as seen in (for example) episodes 8-9.
I believe the white tiger form shows up in episode 22. (Not to be confused with another character’s Bengal tiger.)