Naruto vs Honkai Impact 3rd

Connection:

Both are veteran, battle-hardened warriors who'd live in an era of suffering (The Warring States and the Previous Era (where Honkai first originated from) respectively) yet dreamed of a peaceful world shared by a person they've met (Hashirama Senji and Dr. MEI respectively), yet they're unable to live together due to their status (Madara and Hashirama being from opposite clans, the Uchihas and the Senjus, and are constantly fighting. Whereas Kevin's body became cold to the touch after becoming a MANTIS which results in MEI not being able to make physical contact with Kevin anymore)

Both founded an organization with their partners (Madara and Hashirama created Konoha, where Kevin and Dr. MEI formed the Thirteen Flame-Chasers), but things took a turn for the worst when their loved ones died (Madara's brother Izuna and Kevin's lover MEI), which forced them to take down a dark path, which in turn created their plans to save the world (Infinite Tsukuyomi and Project Stigma respectively)

Both their plans were thwarted by their former comrades (Hashirama and Su respectively) and defeated (Hashirama killing Madara, whereas Su trapped Kevin in the Sea of Quanta), but would return and manipulate (Obito Uchiha and Raiden Mei) into joining their organization (Akatsuki and World Serpent respectively). Ironically, both the deuteragonists they swayed bears a strong resemblance to their deceased loved ones (Sasuke looking like Izuna and Mei being the Current Era version of MEI)

Both would use one of their most powerful weapons in the final arc (Ten-Tails and Herrscher of Finality power) to unlock their ultimate forms (Madara's Ten-Tail Jinchuriki form and Diabolic Kevin/Deliverance Mode)

Both are so OP that it took a Deus Ex Machina from their creators to stop them (Madara being betrayed by Black Zetsu so he can revive Kaguya Ootsutsuki, while the Hyperior ship getting power from literally the entire world to break Kevin's forcefield). Both would see the error of their ways and went to the afterlife, but not before being comforted by the one they knew most (Hashirama and MEI)