I'm taking a break from keeping the theme updated and will be recreating a version for BetterDiscord 2 when it's released. Feel free to fork the project if you're interested in creating a new version.
AccraZed also has a wonderful NieR theme if you want a maintained alternative: https://github.com/AccraZed/YoRHA-UI-BetterDiscord
A Better Discord theme based on the UI from NieR: Automata.
Note: This is my first theme, so the code is sloppy and there will be bugs. Feel free to open up an issue if you find anything you feel could be improved or needs attention.