Complex sentence: There are also numerous direct descendants of Chingis Khan who had formed the ruling class of the Khalkha Mongols prior to the 20th century, but they are also counted as Khalkha Mongols rather than belonging to a special unit.
Split into simpler sentences: There are also numerous direct descendants of Chingis Khan who had formed the ruling class of the Khalkha Mongols prior to the 20th century. They are also counted as Khalkha Mongols rather than belonging to a special unit.