They arrive in silence and darkness. They descend from the skies. They have a hunger for human flesh. They are everywhere. They are parasites, alien creatures who must invade–and take control of–a human host to survive. And once they have infected their victims, they can assume any deadly form they choose: monsters with giant teeth, winged demons, creatures with blades for hands. But most have chosen to conceal their lethal purpose behind ordinary human faces. So no one knows their secret–except an ordinary high school student. Shin is battling for control of his own body against an alien parasite, but can he find a way to warn humanity of the horrors to come?
(Source: Del Rey)

Set around the year 20xx, where Black Jack nearly 60 years old.

Fuuko is a shy girl--so shy that she has trouble talking to strangers. Determined to change herself, she starts working as a waitress at Café Rhodos. The people she meets on and off the job will lead her through the often frightful world of adolescence, and beyond.

Adventures of a young warrior set in Warring States Era.

Historie takes place in ancient Greece and follows the life and childhood of Eumenes, who historically was the secretary and general to Alexander the Great. Historie includes characters such as Aristotle and King Philip II of Macedon and begins around 343 BC, which was a time of Macedonian expansion.

Yuki no Touge:
In the end of the Sengoku period, the great daimyo family of Satake is driven away from Hitachi-no-kuni to Dewa-no-kuni after the Sekigahara battle. They plan to build a new castle there, but the head of the family, Yoshinobu Satake, listens more to the young vassals' advice than that of the experienced chief vassals'. The experienced vassals oppose and start to plan something to defend their place...
Tsurugi no Mai:
It's Sengoku period. Haruna, a daughter of a farmer family, gets herself raped and her family killed by hooligan warriors in the chaos of war. Using the funds she got of the Go stones stolen from the warriors, she joins the dojo of the famous Nobutsuna Kamiizumi to learn kenjutsu in order to get revenge on the warriors. There, she meets Kamiizumi's apprentice Kagekane Hikita, who starts to teach her the art of the sword with the shinai that Kamiizumi has just invented...
(Translated and edited from the Japanese Wikipedia)

Basically, some humans have the ability to negate a sphere of reality, neatly removing it from existence. This gradually alters their appearance until they become a hideous alien, with a giant eye in their forehead.

Heureka is a manga set in antiquity, during the Second Punic War between the small city state of Syracuse and the Roman Empire. The comic is based around the life and times of the famous mathematician Archimedes. Archimedes was not only a gifted mathematician but also an engineer of repute. During the conflict with the Romans, Archimedes was supposedly responsible for creating a number of war machines that devastated the Roman legions before they eventually got the upper hand. The exact nature and use of these devices is controversial, and exists more in the realm of legend than actual historical fact.

A selection of short stories. The stories deal with the same themes as Parasyte and his other work, and in only one of them is his art style noticeably more primitive.