The Yan family had guarded the border areas of Dachu for many years and were loyal ministers. They were also the best candidates for the regent. Therefore, the eldest son of the Yan family became the regent to assist the young emperor.
When the prince of Da Chu first met Yan's eldest son, he never felt any fear. Later, he trusted him so much that he lost all his heart.
Purpose: Having a soft spot is the motivation to persevere