Emperor Taiwu had Helian Chang's brothers put to death. Also in spring 434, after initially refusing a peace offer from Northern Yan, Emperor Taiwu accepted after Feng Hong made an offer to give his daughter to Emperor Taiwu as a consort and returned the detained Northern Wei ambassador Huniuyu Shimen (忽忸于什門), who had been imprisoned by Feng Hong's brother and predecessor Feng Ba in 414 after being commissioned by Emperor Mingyuan. Emperor Taiwu, however, ordered Feng Hong to also send his crown prince Feng Wangren (馮王仁) to Pingcheng to meet him, and Feng Hong refused, ending the brief peace, and by summer 434, Northern Wei resumed its periodic attacks on Northern Yan. Meanwhile, around this time, he also took the sister of Rouran Chilian Khan Yujiulü Wuti, Lu Zuo Zhaoyi, as an imperial consort and married his sister or cousin Princess Xihai to Yujiulü Wuti, to further cement the peaceful relations. In fall 434, while attacking the Xiongnu rebel Bai Long (白龍), Emperor Taiwu took Bai's forces lightly, and was nearly captured in an ambush, saved only by the efforts of his guard Houmochen Jian (侯莫陳建). He subsequently defeated Bai and slaughtered Bai's tribe. In 436, Feng Hong sent another embassy, offering to send Feng Wangren as a hostage. Emperor Taiwu, not believing in Feng Hong's offer, refused, and prepared a final assault. When he arrived at Helong, however, Feng Hong had already requested assistance from Goguryeo, which sent troops to assist Feng Hong's plans of relocating his people to Goguryeo soil, and because Emperor Taiwu's general Tuxi Bi was drunk, the Northern Wei forces could not give chase, and in anger, Emperor Taiwu imprisoned and then demoted both Tuxi and his deputy, the general E Qing (娥清) to being common soldiers, although he subsequently made them generals again. He then sent messengers to Goguryeo, demanding that Goguryeo turn Feng Hong over. Goguryeo's King Jangsu refused, albeit humbly requesting to serve Emperor Taiwu together with Feng Hong. Emperor Taiwu, at the suggestion of his brother Tuoba Pi (拓拔丕) the Prince of Leping, did not immediately carry out a campaign against Goguryeo. (By 438, however, Feng Hong and Goguryeo would have a fall out, and King Jangsu would have Feng Hong executed.) In late 436, the peaceful relations that Northern Wei had with Rouran since 431 ended, for reasons no longer known. Rouran continued its harassment of Northern Wei's northern border