Invincible finds out that Cecil Stedman has recruited the new Darkwing into his services, even after Invincible caught him murdering people who committed small crimes. When Invincible confronted Cecil about this, D.A. Sinclair, another villain that Invincible captured for experimenting on live people, wandered into the room, and this was the final straw for Invincible.
Cecil, as a precaution, lured Invincible into a trap with an army of Reanimen.
From – Invincible #49