Since Feng Luan already made her appearance and finished off a demon king from the Merman Race with a single strike, there was no way the Merman Demon Thearch could avoid the battle. If he didn't do anything, the merman army would be defeated for sure. Out of the fifty thousand members they had present right now, only God knew how many would be able to return to the sea if they were defeated.
If they were to retreat right now, the members of the Merman Race on the front lines would be decimated. They would end this battle as the losers. This wasn't the outcome the Merman Demon Thearch wanted, which was why he had to fight to the death here.
"Feng Clan's little hussy, come up and face me!"