Teen Titans: The Lazarus Contract Special #1

Deathstroke travels back in time repeatedly to try and prevent Grant's death but fails each time. The Teen Titans and Titans join forces to stop Deathstroke and travel back to a time before the original Teen Titans first met Deathstroke; Robin kills Kid Flash to change the timeline, jettisoning Deathstroke back to the present, while Kid Flash is revived. Deathstroke is lost in the Speed Force but the Titans join forces to rescue him. After his exposure to a higher consciousness within the Speed Force, Slade declares he's done being Deathstroke.