Swagatalakshmi Roychowdhury
Ace of the Diamond
One might expect outright hatred between Eijun Sawamura, a passionate and hot-headed pitcher, and Satoru Furuya, a naturally talented but stoic pitcher. Both join Seidou High School’s prestigious baseball team and aim for the same goal: to become the team’s “ace”, the number-one pitcher who leads the team to victory. Despite the competition, they still seem to share a happy bond, competing with each other in a healthy way.
Naruto
In Naruto, Sakura Haruno and Ino Yamanaka start out as childhood friends, but their bond takes a hit when they both develop a crush on Sasuke Uchiha. What was once a close friendship slowly turns into a rivalry, only to become one of the strongest and most enduring in the Hidden Leaf Village.
Mobile Suit Gundam Seed
Athrun and Kira were strong buddies growing up. Their bond meant so much to Athrun that he gifted Kira his awesome robotic bird as a symbol of it. So, naturally it was quite the fight they had when they confronted each other in the battlefield years later.
Bloom Into You
Touko and Sayaka are best friends who have a competitive dynamic in the academic setting. Even though Sayaka does not fare as well, Touko credits Sayaka as the driving force behind her success, thanks to the competition.
Kaguya-sama: Love Is War
Kaguya and Shirogane constantly play mind games on each other to trick the other into confessing their love, but over time their love and admiration grow, beyond just superficial things like appearances.