What characteristics of Mongols may have helped them conquer and rule a great
part of Asia ?

The Mongol empire spared teachers of taxation and led to the great spread of printing all over East Asia. They also helped the rise of an educated class in Korea. ... Under Mongols there was a fantastic “free trade area” that connected most of the known world.

after the roman empire, the catholic church began to unify by taking on many duties of a government.