Naninovel
Naninovel is an extension for Unity to create Visual Novels. The extension costs between 70€ and 140€ (depending on whether or not it's on discount). For more information, see https://naninovel.com/.
Games made with Visual Novel Maker
How it works
The Naninovel extension for Unity consists of a C# framework and some editor utilities.
You define actors (characters, backgrounds, text printers, etc.) as Prefabs in Unity and then write scenes that use the actors in naninovel scripts. Naninovel scripts use commands to direct scenes and even menus.

Combined with the usual functionalities of Unity, Naninovel becomes a powerful tool that supports variables, complex logic, and customizations for almost everything.

Tutorials
- Guide: https://naninovel.com/guide/
- Getting Started: https://naninovel.com/guide/getting-started