Lucius is a stealth adventure game featuring a six-year-old boy who is revealed to be the son of the devil. Lucius Wagner must use a combination of psychic powers (such as telekinesis, combustion, and mind-control) and clever thinking to murder victims in a large estate called Dante Manor for his father Lucifer. At the same time, he must cover his tracks so he is not suspected of performing these atrocities. As a result, most of the deaths seems like accidents. All the victims are somehow connected to Lucius. Most of them are living in the same manor, either as family or servants of the family.
The game incorporates puzzles that can be solved through gathered items that are stored in the inventory. In addition Lucius can receive gifts by completing chores assigned to him by the family members. Some environments contain crosses that damage Lucius. They need to be avoided or neutralized in order to progress. There are nine chapters in total.