Answer:
The Tangut Empire.
Explanation:
Also known as Western Xia it was en empire located in the regions of China and Mongolia. That empire along with the Jin Dynasty from China formed a coalition to resist against the Mongols leader by Genghis Khan. The motive of the war was the refusal of the Tanguts to take part in a previous war on behalf of the Mongols.
Genghis Khan died in August of 1227 during the attack to the capital of the Tangut Empire. The cause of his death remains a mystery. What is not a mystery is that on his deathbed he ordered his army to wipe out the Tangut Empire. The task that was performed by Mongol troops after the death of Genghis Khan.
I hope this answer helps you.
