Northern Mang was not destroyed. The ending of Sword Snow Stride " was that the world was at peace, and the Northern Liang protected the gate for Liyang, and the Northern Mang did not trample the Central Plains. Xu Fengnian led his family to live in seclusion in the mountains. The new generation of youths from Northern Liang entered the imperial court of Liyang, and their careers were bright.

Beiliang and Beimang were enemies. Northern Liang was the fief of a king with a different surname in the Liyang Dynasty. It was relatively independent, but it still belonged to the Liyang Dynasty in name. The Northern Mang was the enemy of the Liyang Dynasty and had been attacking the Northern Liang. According to the ending of << The Sword Snow Stride >>, the Northern Liang won and defeated the Northern Mang army.
Northern Liang had lost a large number of soldiers in the two Great Wars of Liangmang. In the first Great Battle of Liang Mang, the Northern Liang defeated the Northern Mang with an absolute disadvantage in numbers, but the price they paid was huge. It was reported that the border troops of the three states of Beiliang had lost more than 100,000 men, while the Northern Mang had lost 350,000 men. In the second Great Battle of Liangmang, there was no mention of the general losses. However, it could be seen that Beiliang had fought to the death in Youzhou, Liuzhou, Liangzhou and other places, and many soldiers had died in the battles. In short, the Northern Liang had paid a huge price in the two Great Wars of the Liang Mang, but they had successfully resisted the invasion of the Northern Mang.
The Northern Mang Female Empress was a character in Sword Snow Stride ". She was the Female Empress of the Northern Mang Kingdom and one of the most powerful people in the story. She had an emotional entanglement with Xu Xiao, but in the end, it didn't work out. The Northern Mang Female Empress chose to look for Xu Xiao after he died. She didn't want to continue living and didn't want to see Northern Liang fail. After she died, Beimang would destroy Beiliang and go south. The search results didn't provide any specific information about the Northern Mang Empress's ending or her relationship with Xu Xiao.
In the end, Northern Wei was destroyed by Northern Zhou. In 557 AD, Yuwen Yong of the Northern Zhou Dynasty launched an attack on the Northern Wei Dynasty. After several years of fighting, the Northern Wei Dynasty was finally defeated. The last emperor of the Northern Wei Dynasty, Yuan Kuo, committed suicide.
Northern Wei was eventually destroyed by Northern Zhou.
The free anime of the second season of the " Sword Snow Stride " can be watched on platforms such as Kuwo Changting.