He is the newly succeeded king of Li Kingdom, but he ignores the regent's eye for the throne.
He was Suiyan's most trusted guard, but he turned a blind eye to Suiyan's love.
He was the criminal who attacked and destroyed Li Country, but he only wanted to let Suiyan's eyes linger.
The world scolded Sui Yan, scolding him for being stupid and ignorant, and playing songs every night, but who knew that he was just saying these words before his mother died:
"Yan'er, be a fool."
When Dongli betrayed him, when everyone turned their backs on him, he could laugh at himself and leave without any regrets.