After watching Under the Red Hood and hearing Rha's explanation for what happened, it got me to thinking:

has there ever been a time when Rha's thought that the Joker might be a threat to his plans and sought to have him killed?

OR

Would Rha's have Joker killed as a favor of sorts to Bruce? Bruce won't kill the Joker, but Rha's has few qualms about killing and the Joker is a sick man. It could be interesting to see Rha's kill the Joker and see what Bruce would do. Would he go after Rha's and dunk the Joker into the Lazarus Pit or let Joker stay dead?