Adult PC Game: Abaddon: Princess of the Decay - Final by Sakuraprin Archive

Overview:
I could still live in peace... if I never learned the truth...
This tale is set in the haunted Ayakoji Mansion, nestled away deep in a dense, dark forest. Professor Yamanobe, a close friend of the mansion's owner, arrives at the mansion with a small group of his students to explore and learn the truth behind its many rumors and mysteries. However, they too are engulfed by the innumerable horrors lurking within before long...
It is then that Homura, Professor Yamanobe's son, arrives with a small group of his friends in search of his father. Will they be able to find his father and escape alive? Or will they suffer an unthinkable, sinister fate...?​

Abaddon: Princess of the Decay - Final by Sakuraprin Gameplay Preview