The song is called "The Advisers Alliance Main Theme".

"The Advisers Alliance Main Theme" is composed by S.E.N.S. (神思者) and composed by S.E.N.S. "Yin", released on December 28, 2017.

Extended information:

Related introduction to the 21st episode of the TV series "Tiger Roars and Dragon Roar":

In order to provoke the Wei army to send troops, Zhuge Liang used the method of provoking the generals. He sent an envoy He sent Sima Yi a dress, but Sima Yi wore it calmly. Sima Yi wore a girl's skirt and looked across the river from Zhuge Liang. He recited the "Execution of the Master" in public, and Zhuge Liang was stimulated to cough up blood and fainted. Sima Yi wore a female skirt, which depressed the morale of the army. That night, he and Zhuge Liang had a spiritual dialogue while looking at the moon in the sky.

Bixie arrived at the Wei army camp to read out the imperial edict. Cao Rui ordered Sima Yi to defeat Zhuge Liang within ten days, while Cao Shuang was already on his way to Chang'an. Zhang Chunhua sent Sima Zhao, who was recovering from his injury, back to the military camp. She held up a whip to question Sima Yi. Zhuge Liang was so angry that he fainted after learning about the defeat of Soochow. He knew that his time was running out, so he entrusted the great cause of Shu to Jiang Wei.