太武帝
At this time, Western Qin not only had to face Northern Liang attacks, but had suffered a major earthquake in late 429 and a major drought for most of 430 as well. Most of Qifu Mumo's people fled. He felt that his state could no longer stand. He sent his officials Wang Kai (王愷) and Wuna Tian (烏訥闐) to submit to Northern Wei, requesting Northern Wei troops to escort him to Northern Wei territory. Emperor Taiwu of Northern Wei was pleased, and promised that after he can destroy Xia, he would bestow Xia's Pingliang (平涼) and Anding (安定) Commanderies (collectively roughly modern Pingliang, Gansu) as Qifu Mumo's domain. Qifu Mumo therefore destroyed his own royal treasury and set Fuhan ablaze, heading east with the only 15,000 households that remained under him, to try to join Northern Wei troops at Shanggui (上邽, in modern Tianshui, Gansu), but the Xia emperor Helian Ding (Helian Chang's brother and successor), upon hearing this, engaged him and stopped his advances, and he was forced to take up defensive position at Nan'an. By this point, Nan'an was all he could hold; all of his old territory in the west had been seized by Tuyuhun.