Final answer:
Mencius, also known as Mengzi, is a follower of Confucius who advocated the innate goodness of human nature and the focus on righteous conduct, known as yi, which differentiates him from other thinkers like Xunzi and Mozi.
Step-by-step explanation:
The follower of Confucius who added the belief in the goodness of human nature and his focus on the virtue of righteous conduct or yi was Mencius. Mencius, also known as Mengzi, expanded Confucius's teachings and is well-known for his doctrine that human beings are innately benevolent, implying an inherent tendency toward the five constant virtues.
Mencius is famous for his idea that humans naturally have a disposition toward compassion and righteousness, contrasting with other philosophers like Xunzi, who believed that human nature is primarily detestable, and Mozi, who opposed hierarchical structures in favor of universal love and rational ethics.