Complex sentence: Hennig signed with World Championship Wrestling (WCW) in 1997, and since he could no longer be billed as Mr. Perfect as that moniker was trademarked by the WWF; he returned to wrestling under his real name for the first time since the late 1980s.
Split into simpler sentences: Hennig signed with World Championship Wrestling (WCW) in 1997. Since he could no longer be billed as Mr. Perfect, as that moniker was trademarked by the WWF, he returned to wrestling under his real name for the first time since the late 1980s.