Now that the Robin, the brutal vigilante Scarlet.
After coming back to life, Jason Todd carried a deep grudge over his beating and death at the hands of the Joker in the "Death of the Family" story arc. His initial time back in the land of the living was marked by a spree of brutality to show how much more effective he was at stopping crime using the lethal methods the Bat-Family refuses to employ. As the Red Hood, he became one of the most ferocious antiheroes in the DC Universe. But as time went on and his family intervened, he slowly began to move away from killing. Red Hood still has other hardcore fighting techniques, but he has sworn off guns and made a concentrated effort to curb his worst impulses and avoid ending the lives of Gotham's villains.
While it's a good thing Jason has tried taking a step back from killing, he's got one loose end he really need to address. In Batman and Robin #3 by Grant Morrison and Frank Quitely, Jason comes across Sasha, a young woman who has been mutilated, along with her father, by Professor Pyg. Todd offers her a chance to channel the rage she feels by taking her on as his new partner. With the new identity of Scarlet, she becomes an integral part of Red Hood's new campaign to be Gotham's number one protector after Batman is presumed dead. Jason trains Sasha to fight and gives her a pair of blades, turning her into as much a ruthless killer as he is. With Scarlet's assistance, Red Hood is able to take out more villains and mob figures than he ever did on his own.
Sasha was forced to leave Gotham after Jason was arrested, though she did briefly return and the two were reunited after he broke out of prison. However, DC's New 52 reboot split the two up again and aside from a small appearance during the Convergence event, Scarlet hasn't been seen since. While Professor Pyg's damage was hinted to be impermanent, Sasha was still involved in Jason's most harrowing deeds, and exists as an unknown quantity and, arguably, a major victim of his darkest period.
It's no wonder Jason picked Sasha to be his Robin. They both lost parents to crime and were filled with anger at the world. While taking her in may have had a degree of honor, turning her into a killer was a poor decision that he has yet to make up for. While her current status in Infinite Frontier canon hangs in limbo, the era has taken pains to recognize as many past stories as possible. It's reasonable for fans to assume that Red Hood's lethal Robin is still out there somewhere, living with the consequences of ing his crusade.
Scarlet returning and Red Hood showing her a better path would be a great way to show that Jason is truly moving on from his villainous past. Allowing Jason's one-time Robin to return and force him to reckon with his deeds could present a fantastic opportunity to explore who Red Hood is, and how he can truly make amends for his past.
