Shin Megami Tensei: Devil Children Black Book/Red Book/White Book is a Japan-only role-playing video game from the Megami Tensei series. Three versions of the game were released. Red Book and Black Book came out first, each with different main characters. A third, White Book, was released after the first two, featuring a third character. Red and Black were then bundled together for the PlayStation. The PlayStation remake features the Japanese voice actor from the anime. The PlayStation version has also been available on the Japanese PlayStation Store since October 13, 2010.
Each game features a different Devil Child, a child who is half demon, half human. The humans collect monsters (who speak human language, like in Digimon). The game takes place in a place called Makai in modern Japan, like most Megami Tensei games. The Devil Riser holds their partner demon(仲魔(Nakama, a pun on the word "仲間", replacing the character "間", meaning "interval, relationship", with "魔", meaning "demon").
Source: Wikipedia, "Shin Megami Tensei: Devil Children", available under the CC-BY-SA License.