Altus代表作品之一《數位惡魔物語 女神轉生》在1987年首次在FC平台推出，遊戲劇情是由西谷史在1986年推出的同名小說改編，畫面採用3D迷宮進行，其它特色則是可惡魔召喚及對話，更可進行惡魔合體或將惡魔拉進團隊，靈活運用魔法系統將有利於戰鬥。目前遊戲IP屬於SEGA SAMMY控股公司。 

Altus之後為拓展兒童市場，推出《真·女神轉生》惡魔之子系列。從2000~2004年密集推出相關遊戲。2000年在GB上市的是黑之書、赤之書，隔年則是白之書，2002年是光之書、闇之書(GBA)。2003年在手機平台上架的有GBA炎之書、冰之書，Puzzle de Call!、2004年的Messiah Riser跟直到2011年的《真·女神轉生》惡魔之子都是在手機上推出。該系列還有推出動漫及漫畫，當時買漫畫單發行本會贈送卡片。

劇情設在西元200X的十月，在REM小學教室，老師向全班介紹新來的轉校生Amy Kahihara，她被分配到跟主角Akira一起坐。下課後離開教室，會碰到主線人物Jin，表示Lena發現一些不尋常的東西，在圖書館內有一本描述惡魔的書，書中有可以召喚出惡魔的咒語。這時候新同學Amy也加入，一行人來到圖書館的書架卻沒找到書，原來是被管理員收起來。 

書架上可以找到一些道具，當Akira跟Jin念咒語時，石像怪(Gargoyle)成功被召喚出來，沒想到惡魔認識新同學Amy，並想將她強行帶回華海拉殿(Valhalla:北歐神話的歐汀神會見英勇戰死勇士的地方）。當戰鬥無法避免時，Amy提供Demiloc跟Vinecom的裝置，透過Demiloc進行召喚Gale， 發現原來主角是半魔半人的小孩(DemiKid)，Amy告訴大家Jin也是擁有惡魔血統的人類。擊敗石像怪後，得知時間裂口出現。大家需要協助修復時間裂口，否則未來世界即將消失。前往學校屋頂，發現穿越入口，進去就可以抵達惡魔世界，冒險就此展開。 

副畫面顯示的指令有1.通訊(Vinecom):點進去可看到全組狀態及惡魔收集等2.魔法(Magic) 3.物品(Item) 4.設定(Setup) 5.存檔(Save)。戰鬥畫面的指令有 戰鬥(Battle)、自動(Auto)、招募(Recruit)、連續(Combo)、逃跑(Run)、狀態(Status)。 

遊戲魔鬼召喚有類似寶可夢的概念，之後持續推出多款續作，因為鎖定的市場是兒童，所以沒有任何恐怖劇情，連主線人物們的設定也都是小學生。

One of Altus' notable games, "Digital Devil Story: Megami Tensei," was first released on the FC platform in 1987. The storyline is adapted from a novel of the same name by Aya Nishitani, published in 1986. The gameplay features a 3D dungeon perspective, and its unique elements include demon summoning and negotiation, as well as the ability to fuse demons or recruit them into your team. Effective use of the magic system is crucial for battles. Currently, the game's IP is owned by SEGA SAMMY Holdings.

To expand into the children's market, Altus later released the "Shin Megami Tensei: Devil Children" series. From 2000 to 2004, several related games were released. In 2000, the Black Book and Red Book were launched for the GB, followed by the White Book in the next year. In 2002, the Light Book and Dark Book (GBA) were released. In 2003, the GBA titles Flame Book, Ice Book, and Puzzle de Call! were launched on mobile platforms, followed by Messiah Riser in 2004. The series continued on mobile platforms until 2011 with "Shin Megami Tensei: Devil Children." The series also spawned anime and manga adaptations, with collectible cards included with manga single volumes.

The story is set in October 200X at REM Elementary School, where the teacher introduces a new transfer student, Amy Kahihara, to the class. She is assigned to sit next to the protagonist, Akira. After class, they encounter Jin, a main character, who mentions that Lena has found something unusual—a book in the library that describes demons and contains summoning spells. Amy joins them as they head to the library, but they can't find the book since the librarian has taken it away.

In the library, they find some items on the shelves. When Akira and Jin recite the spell, a Gargoyle is successfully summoned. To their surprise, the demon recognizes Amy and attempts to take her back to Valhalla (a hall in Norse mythology where Odin receives the souls of slain warriors). As the battle becomes unavoidable, Amy provides devices called Demiloc and Vinecom. Using Demiloc, they summon Gale and discover that Akira is a half-demon, half-human child (DemiKid). Amy reveals that Jin also possesses demon blood. After defeating the Gargoyle, they learn about a time rift that needs to be repaired to prevent the future world from disappearing. They head to the school rooftop, find the entrance to the demon world, and their adventure begins.

The secondary screen displays commands such as 1. Communication (Vinecom): View team status and demon collection, 2. Magic, 3. Items, 4. Setup, and 5. Save. The battle screen commands include Battle, Auto, Recruit, Combo, Run, and Status.

The game's demon summoning concept is similar to Pokémon. Many sequels were released, targeting the children's market, which is why there are no horror elements. The main characters are all elementary school students.