But how would they know Undetaker's past? Okay they had a past as children but the only person who'd know that is Paul Bearer. All that is known is the story about the house burning down when they were kids.. It would be interesting if there was another sibling - even cooler if it was a female since there could be an amazing "dark female" persona. Paul Bearer could bring her back or she could return herself whilst one of them or both of them (as a tag team) are having a huge match, causing them to lose.