Not sure if this is rare but I got Umbral Rose on my first supply from the expansion : r/honkaiimpact3
Umbral Rose | Houkai Impact 3rd Wiki | Fandom
Umbral Rose - Official Honkai Impact 3 Wiki
Umbral Rose: Scythe-wielding battlesuit | A-rank Umbral Rose is the first scythe-wielding battlesuit, as well as Rita's first battlesuit. Her Ultimate commands multiple-stage slashes to deal AOE DMG. | By Honkai Impact
rita rossweisse and rita rossweisse (honkai and 1 more) | Danbooru
Honkai Impact 3rd] Umbral Rose by xMayu-Chi on DeviantArt
Asteroid Series Honkai Impact 3rd: Rita Rossweisse Umbral Rose (Re-run)
Guideγ New battlesuit: Umbral Rose - Honkai Impact 3rd - YouTube