Ye Chen was not surprised by their battle. He did not stop them and let them fight.
Because of Kun Peng's words that it would become stronger after devouring the blood, the Titan Ape had been guarding against Kun Peng. When it heard that it wanted to swallow Little Purple and the blood into its stomach, it was instantly excited.
Ye Chen guessed that the Titan Giant Ape's idea was that after Little Purple and its blood were swallowed by the Kun Peng, it would secretly devour some blood to strengthen itself. This belonged to Little Purple and he could not tolerate it. Hence, he directly attacked. He did not expect the Kun Peng's reaction to be so intense. It did not speak but attacked directly.
Kun Peng's thoughts were very simple. There were no blind spots in the space he had opened up. Even if the blood's energy was leaked, it would return to Little Purple. He was wholeheartedly helping Little Purple. He did not expect the Titan Ape to attack without asking.