Justice League of America (1960-) #223

Reena goes to the Arena and turns herself in to Maximus Rex’s guards. Rex, meanwhile, is in the middle of massacring another group of hapless victims inside the fighting pit. Dr. Lovecraft escorts Reena out into the stadium and presents her to Rex. Sneering, Rex brutally finishes off the remaining combatants as a means of showing Reena how he deals with those who betray him.