At the beginning, Liu Bei helped Gongsun Zan defeat Yuan Shao, and when he saw Zhao Yun, he loved it very much, so he was reluctant to separate.
Seeing that Hougongsun Zan withdrew his troops, when Liu Bei and Zhao Yun separated, he held Zhao Yun's hand tightly and shed tears.
After Cao Cao wanted to avenge the killing of his father and conquer Xuzhou, Tao Qian asked Liu Bei for help, Liu Bei then borrowed troops from Gongsun Zhan, and named Zhao Yun to borrow Zhao Yun, after relieving the siege of Xuzhou, Liu Bei and Zhao Yun shed tears again and said goodbye.
The second time in Funiu Mountain, Zhou Cang was injured by Zhao Yun, and moved troops to Guan Yu and Liu Bei, and Liu Bei recognized Zhao Zilong from a long distance.
It shows that Liu Bei has a longing for Zhao Yun engraved in his bones, so much so that after burning Xinye, he completely entrusted his net worth and life to Zhao Yun, and completely regarded Zhao Yun as his brother.
Back then, when Zhao Yun did not follow Liu Bei, Liu Bei's family was in charge of his second brother Guan Yu, and even Zhang Fei couldn't bear this burden, and Zhang Fei almost killed himself because of this.
In addition, when Guan Yunchang learned that the Five Tiger generals were canonized, he said that Zhao Yun "Zilong has been with my brother for a long time, that is, my brother", it can be seen that Guan Yu has regarded Zilong as a brother.
When he was in Changbanpo, Zhao Yun said "Yide save me", indicating that the relationship between Zhao Yun and Liu Bei's three brothers is extraordinary, Yide is the word, like a person's nickname, only the closest family members and the most respected elders will call the nickname, and Zhang Fei's sentence "Zilong goes first, the enemy soldiers are blocked by me", when life and death are at stake, only brothers will protect their families with their lives, and Zhang Fei is called Zhao Yun's word, that is, nickname, if Zhang Fei said,
"Zhao Yun, you go first, and the enemy soldiers will be blocked by me", obviously the meaning of the two sentences is the same, the artistic conception and connotation are completely different, and the relationship will be very different, so Mr. Yuan will say Zhao Yun as Liu Bei's fourth brother. That's how I interpret it, I don't know what the old irons think!