Simplify the following text for a Grade 3 native English-speaking person.
Original: The tag team broke apart when X-Pac turned on Kane and rejoined D-Generation X. Kane and X-Pac then were engaged in a lengthy feud against each other .
Simplified: In 1999 , Kane became a good guy and started to team with X-Pac . The pair was together until X-Pac attacked Kane in 2000 .