Games like Undying Fortress
Games like Undying Fortress include Baldur's Gate 3, Tainted Grail: The Fall of Avalon, Roadwarden, Dragon Age: Origins - Ultimate Edition, and The Life and Suffering of Sir Brante. We matched them by the tags players give Undying Fortress on Steam (RPG, Choose Your Own Adventure, Choices Matter, Text-Based, and Character Customization): closest matches first, and among equally close ones the better-known games.

Baldur's Gate 3
Shared: RPG · Choices Matter · Character Customization

Tainted Grail: The Fall of Avalon
Shared: RPG · Character Customization · Adventure

Roadwarden
Shared: RPG · Text-Based · Choose Your Own Adventure

Dragon Age: Origins - Ultimate Edition
Shared: RPG · Choices Matter · Singleplayer

The Life and Suffering of Sir Brante
Shared: RPG · Choices Matter · Choose Your Own Adventure

The Witcher 3: Wild Hunt — Remastered
Shared: RPG · Choices Matter · Singleplayer

Suzerain
Shared: Choose Your Own Adventure · Choices Matter · RPG

Undertale
Shared: Choices Matter · RPG · Multiple Endings

Legend of Mortal
Shared: RPG · Choices Matter · Multiple Endings

The Witcher 2: Assassins of Kings Enhanced Edition
Shared: RPG · Choices Matter · Singleplayer

The Henry Stickmin Collection
Shared: Choose Your Own Adventure · Multiple Endings · Choices Matter

STAR WARS™ Knights of the Old Republic™ II - The Sith Lords™
Shared: RPG · Choices Matter · Singleplayer

Warhammer 40,000: Rogue Trader
Shared: RPG · Choices Matter · Character Customization

The Test
Shared: Choose Your Own Adventure · Multiple Endings · Choices Matter

Dragon Age™ Inquisition
Shared: RPG · Choices Matter · Character Customization

GreedFall
Shared: RPG · Choices Matter · Character Customization

Hogwarts Legacy
Shared: RPG · Singleplayer · Character Customization

The Witcher: Enhanced Edition Director's Cut
Shared: RPG · Choices Matter · Singleplayer

Reigns
Shared: Choices Matter · Choose Your Own Adventure · RPG

Late Shift
Shared: Choices Matter · Choose Your Own Adventure · Multiple Endings

Kingdom Come: Deliverance
Shared: RPG · Singleplayer · Adventure

Tyranny
Shared: RPG · Choices Matter · Adventure

Mass Effect™ Legendary Edition
Shared: RPG · Choices Matter · Character Customization

Hero's Adventure: Road to Passion
Shared: RPG · Multiple Endings · Choose Your Own Adventure