Complex sentence: Yanda in the Book of Wei, are supposed to be a variety of the Great Yuezhi while the Hua, who are also described, are possibly an offshoot of the Gaoche.
Split into simpler sentences: Yanda in the Book of Wei, are supposed to be a variety of the Great Yuezhi. On the other hand The Hua, who are also described, are possibly an offshoot of the Gaoche.