WARNING! SPOILERS TO TEEN TITANS ANNUAL #2 by Robbie Thompson, Eduardo Panscia, Julio Ferreira, Marcelo Maiolo, and Rob Leigh!
The death of Jason Todd changed Batman and the Bat-Family forever. The murder of the second Robin at the hands of the Joker had a profound effect on the Dark Knight whose memorial to Jason in the Batcave served as a reminder of that which was considered his greatest failure. Although that failure has been softened with the return of Jason as Red Hood who became a controversial ally of the Bat-Family, Batman has revealed that his greatest failure isn't Jason Todd, it is actually his son Damian, the former Robin.
Introduced in Batman #655 as the son of Bruce Wayne and Talia al Ghul, daughter of the immortal Batman enemy Ra's Al Ghul, Damian Wayne was trained from a young age by assassins and intellectuals to be his grandfather's heir. When he was introduced to his father, Bruce hoped working alongside him as Robin would help curb his arrogance and lethal training in hopes of a better path. Like other Robin's before him, Damian had joined the Teen Titans where he became their leader which added a unique edge to the teenage superhero group. Recently, Damian has been taking the Titans in an extreme direction with tactics such as holding their enemies against their will, wiping their minds, and eventually past the point of no return ending with Damian killing longtime Titans enemy Brother Blood and almost killing KGBeast as well.
In Teen Titans Annual #2, Damian is confronted by his father Batman over his actions where the Dark Knight chastises Robin and his fellow Teen Titans for going along with this un-heroic behavior. Still traumatized from witnessing Bane kill Alfred, Damian accuses his father of being afraid. Bruce begins to admit to this before the team is interrupted by Deathstroke's latest attempt to kill the Teen Titans. Surviving the battle, Slade and Damian duke it which is interrupted by the Titans. Damian catches Slade off guard and attempts to kill him but his actions, unfortunately injure Red Arrow who had stepped in hopes of reminding Robin that Titans don't kill, or at least they don't anymore.
With his leadership of the Titans over, Batman returns to continue his talk with Robin where he offers to help Damian before he goes too far. This tender moment becomes the opposite with Damian pummeling his father with blows and accusations that Wayne Manor is nothing more than a tomb and that he is proof that his father's methods do not work, citing the injury and near-death of Nightwing and the death of Alfred as his evidence. Yelling at his father for why he doesn't fight back, Bruce admits it is because he loves Damian and that he knows he has failed him.
Unfortunately, this admission is not enough as Damian denounces his title as Robin, stating that he will never be free until he is no longer under his father's shadow. This failure may indeed haunt Batman even more than any of his previous failures ever will.