This dubius honour, in my opinion goes to none other than Mr.Slade Wilson. He's even beaten Marvel's Corsair in that department !
Do you guys see any hope in future of them getting back together ? Would be really awesome to have Deathstroke, his wife and 3 kids back as a family. TBH it's all Slade's fault for not being there and caring for them when he was needed, but I think there's still room for reconciliation.
Otherwise either both, or at least ONE ( I'm thinking Jericho the telepath ) of his sons are definitely gonna die. The Wilson family, when together as a team are gonna be simply UNSTOPPABLE. DC needs to make that happen. Most badass family in comics ( no really, ALL 5 of them are highly trained Special Operatives, and the MOM was a friggin Special Forces instructor, not to mention the dad being the Naked Snake of DC) !