Conception II is a sci-fi RPG with visual novel and dating sim aspects. The player character awakens to a mysterious power called star energy after the death of his sister, and with this power he is capable of producing "star children" with female classmates through a magic ritual called "classmating" where their power is combined into a special matryoshka vessel.
Together with his female partner and the star children, the player character will explore dungeons located in mysterious phenomena called Dusk Circles and battle against demonic foes within. There are seven heroines to bond with through battle and conversion, and building a relationship with each will lead to stronger star children.
The star children represent 16 different classes divided in Normal, Exceptional and Special types. Like in other RPGs, each class makes use of a unique skill, and players are encouraged to classmate with heroines to create a diverse party of star children they can bring along with them in battle. Star children who are ready to move on from the party can live in the city surrounding the player's high school. The city grows as star children move in, unlocking facilities useful to the player.
The battle system revolves around positioning the party members around enemies to target their Weak Points, while manipulating the turn order to maximize the party's attacks and increase the chances of activating the Chain Drive effect which slows enemies down while boosting the party's rewards earned from battles.
This game is also known as Conception II: Shichisei no Michibiki to Mazuru no Akumu in Japan.