The Skull Man Vol 2

From the Tokyopop edition

As the Skull Man assumes the identity of his dead grandfather, Ryusei Chisato, a young reporter begins investigating the connections to his previous identity, Tatsuo Kagura. The Skull Man has no qualms about shutting her up, but first he must deal with a new villain: Parasite Green. Green possesses a drug that seemingly allows him to control people’s minds, a drug that may have even helped him turn the Skull Man’s own partner, Garo, against him.

Source: Anime News Network Encyclopedia