July 21, 2008 kane and undertaker are not related in way in real life.
10 May 2010 Kane and the Undertaker aren't related. Kane's name is Glen Jacobs, and Taker's name is Mark W. Calaway. However, Paul Bearer was Taker's uncle.
I'm Not positive But I think It was a result of Kane getting undertaker upset and either Kane attacked Taker or Taker Attacked Kane But after Kane and Undertakers Match With Each Other They Came Back...