Before Masud Rana, there was Kuasha. The eerie, morally grey series that shares Rana's creator, his publisher, and, once, his page.
Kuasha (কুয়াশা, "mist" or "fog") is the series Qazi Anwar Hussain launched around 1964, a couple of years before Masud Rana, and also under Sheba Prokashoni. Its title character is a brilliant, mysterious figure who lives in the grey zone between villain and hero: a rogue genius who punishes wrongdoers on his own terms rather than the law's. Pursuing him, and sometimes crossing him, are the detective Shahid Khan and his assistant Kamal.
Where Masud Rana is the globe-trotting government agent, Kuasha is the shadow: colder, stranger and harder to pin down. For many readers that ambiguity is exactly the appeal.
The Kuasha series ran to roughly seventy-eight books and is now closed.
Created by Qazi Anwar Hussain and published by Sheba Prokashoni, just like Masud Rana.
The two worlds meet in the Masud Rana crossover Shei Kuasha (volume 412).
The clearest bridge between the franchises is the Masud Rana volume Shei Kuasha ("That Kuasha," volume 412), a crossover that brings the mist into Rana's world. If you love one series, it is the natural doorway into the other.