QUES: On that very day the army of the Over Herians crossed the border It was a powerful sight

correct the punctuation.

CORRECTED: On that very day, the army of the Over Herians crossed the border. It was a powerful sight.

QUES: Along the way he also became a poet

correct the punctuation.

CORRECTED: Along the way he also became a poet.

QUES: It accounts for more than 13000 new cases of leukemia each year

correct the punctuation.

CORRECTED:
It accounts for more than 13,000 new cases of leukemia each year.