In DGSD, Xiao Feng met this Jurchen guy, Wanyan Aguda. Later he became sworn brothers with the Liao Emperor Yelu Hongji.
What I am curious about is, later on in LOCH/ROCH, Wanyan seems to have become a Liao surname (Wanyan Honglie et al) and Yelu, a Mongolian one (Yelu Chucai et al). Were these surnames common to a few races? Or was this the result of conquering weaker territories?
Thanks.