KIDŌ SENSHI GUNDAM: THUNDERBOLT - GAIDEN

Proper Japanese Title: 機動戦士ガンダム サンダーボルト 外伝 Originally serialized in eBigComic4. Spin-off of Kidō Senshi Gundam: Thunderbolt. — Description from Comic Vine community (comicvine.gamespot.com · https://comicvine.gamespot.com/kido-senshi-gundam-thunderbolt-gaiden/4050-161808/).