Suggested by iKnowledge Both of these guys are some of Batman’s most dangerous enemies. While Joker did best Deathstroke in the only time that they’ve fought (To my knowledge) Deathstroke wasn’t exactly prepared for that battle. In his Trigon form, Slade has amped up strength and some mild healing regeneration. Coupled with his own formidable skills I believe that will be enough to take Joker down. Joker’s good, but he simply isn’t good enough. Slade wins.