Nikolai Krasotkin, a Russian secret agent, guides John Watson and Frederick Burnaby on their mission to locate the corpse engineer Alexei Karamazov in Kabul. He maintains a cynical worldview and frequently engages in philosophical reflections on society and human nature during interactions with his companions.

While traversing the Khyber Pass, the group is ambushed by enhanced corpses exhibiting limited intelligence and rescued by Hadaly Lilith. They successfully locate Alexei Karamazov. The following day, Watson and Friday discover Karamazov forcibly experimenting on the still-living Nikolai. This procedure kills Nikolai and reanimates him as a more advanced corpse capable of rudimentary thought and speech.

After Watson rejects the notion that this procedure aligns with Victor Frankenstein's original research, Karamazov commits suicide by instructing the corpsified Nikolai to forcibly upgrade him. Before dying, Karamazov reveals the Frankenstein Memorandum is located in Japan and commands Watson to destroy it. Nikolai's existence as a reanimated corpse concludes at this point.

The character draws inspiration from Nikolai "Kolya" Ivanov Krasotkin in Fyodor Dostoevsky's novel *The Brothers Karamazov*, though this literary connection does not form part of his depicted background within the film's storyline.