Ryuu to Sobakasu no Hime (MyAnimeList)

Contain : Audio (256 kbps Opus 5.1) : English, Japanese

→ How to use :

• Copy the .mka files in the same folder as the .mkv video files
• If needed, rename the .mka files to whatever the .mkv files are named
• Enjoy

If your player doesn't recognize the files even after this, try :

• changing MPV's config file

TLDR : add these two lines in your mpv.conf file : audio-file-auto=fuzzy sub-auto=fuzzy

• playing an external audio track with VLC
• Using MKVToolNix GUI to remux the files together