The term 'Calculus Developer' refers to the mathematician Leonhard Euler (1707-1783), who is widely considered to be one of the greatest mathematicians of all time. He was a Swiss-born mathematician, physicist, astronomer, logician and engineer who made important contributions to the fields of calculus, number theory, and graph theory. He is best known for his work on the development of calculus, which he developed independently of Isaac Newton. He also made significant contributions to the field of graph theory, including the Euler Path and Euler Circuit. His work has had a lasting impact on mathematics and science, and he is remembered as one of the most influential mathematicians in history.