Games like Novena Diabolos
Games like Novena Diabolos include Darkwood, Tales of the Black Forest, Outlast, Danganronpa 2: Goodbye Despair, and Tiny Bunny. We matched them by the tags players give Novena Diabolos on Steam (Adventure, Visual Novel, RPG, Horror, and Anime): closest matches first, and among equally close ones the better-known games.

Darkwood
Shared: Adventure · Horror · Survival Horror

Tales of the Black Forest
Shared: RPG · Adventure · Horror

Outlast
Shared: Horror · Survival Horror · Atmospheric

Danganronpa 2: Goodbye Despair
Shared: Visual Novel · Anime · Adventure

Tiny Bunny
Shared: Visual Novel · Horror · Atmospheric

Look Outside
Shared: RPG · Horror · Adventure

Poppy Playtime
Shared: Horror · Survival Horror · Adventure

The Forest
Shared: Horror · Adventure · Survival

The Coma 2: Vicious Sisters
Shared: Adventure · Horror · Survival Horror

Danganronpa: Trigger Happy Havoc
Shared: Visual Novel · Anime · Adventure

Sanfu
Shared: RPG · Adventure · Visual Novel

Don't Starve Together
Shared: Adventure · Survival · RPG

Firework
Shared: Horror · Visual Novel · 2D

The Deed
Shared: Adventure · RPG · Visual Novel

Return to Shironagasu Island
Shared: Adventure · Visual Novel · Horror

Raging Loop
Shared: Visual Novel · Adventure · Atmospheric

The Witch's House MV
Shared: Horror · RPG · Adventure

Little Nightmares
Shared: Adventure · Horror · Atmospheric

Mad Father
Shared: Horror · Anime · Adventure

Danganronpa V3: Killing Harmony
Shared: Visual Novel · Anime · Horror

Phoenix Wright: Ace Attorney Trilogy
Shared: Visual Novel · Anime · Adventure

Corpse Party
Shared: Horror · Visual Novel · Anime

Dying Light
Shared: Horror · Survival Horror · Survival

Sally Face - Episode One
Shared: Horror · Adventure · Dark