Complex sentence: Later that year, he would sign a contract with World Championship Wrestling (WCW), and would work for them until 1998, when he decided to retire from wrestling as "His Head was battered" from the business.
Split into simpler sentences: Later that year, he would sign a contract with World Championship Wrestling (WCW). He would work for them until 1998, when he decided to retire from wrestling as "His Head was battered" from the business.