#1 Kane
When Kane made his WWE debut in 1997, fans were legitimately terrified of his monstrous presence. He was billed as the younger half-brother of The Undertaker, The Big Red Machine quickly jumped right into the main event scene.
A top AEW star just called one of his colleagues 'spoiled' and 'narcissistic' HERE.
However, as time went on, the character evolved and went through some rather significant changes.
After not capturing any major title for several years, he floated around in the mid-card and teamed up with Rob Van Dam for most of 2003. He then lost a title match against Triple H on RAW in 2003, and Kane was forced to unmask after the match in front of millions of people.
Since then, Kane has been used as a stepping stone either to put over younger talent or make other contemporaries look dominant--especially with his corporate gimmick which saw him lose most of his matches.