Are There 2 Undertakers In Wwf?

Hey fellow nairalanders who watch wrestling. I'd like to know: how many Undertakers are there at WWF? It's little bit confusing to me;one comes with caskets and seldom talks,the other sometimes is on a bike and talks more freely. Are they two? And whats Undertaker's relationship with the wrestler called Kane?

yeah like he said same person, and i think undertaker and kane are brothers