#4 The Undertaker and Kane
Kane and The Undertaker are very good friends in real life. The first time they met was in 1995, in Smoky Mountain Wrestling when 'Taker defeated Kane, who was billed as 'Unabom'. Fast forward today and the two are still friends. Kane stood in The Phenom's corner at WWE Super-Show Down and they reunited as The Brothers of Destruction to take on DX at WWE Crown Jewel.
Also read: 3 Reasons why Kane should've ended the Undertaker's WrestleMania streak
At one point, Undertaker had brought up the idea of Kane being the one to end his WrestleMania streak, but Kane declined because he had so much respect for his storyline brother and real-life friend. In the storyline side of things, they were two monsters who tried to tear each other apart several times. They went on to team up and even won the WWE and WCW tag team titles.
On an interesting note, The Undertaker was originally billed as "Kane The Undertaker" before his televised debut in 1990, but the Kane name was removed shortly before he made his debut and it was given to his new storyline half-brother in 1997. 'Taker even supported Glenn Jacobs on his run for mayor of Knox County in 2018.