Against a powerful adversary, splitting the army was a huge taboo. Daliang City contained One-hundred and ten-thousand elites, Saleen was going to take away fifty-thousand of them and twenty-thousand auxiliary troops. That meant that Daliang City would be left with sixty-thousand main soldiers.
Saleen was not worried, his fifty-thousand men, which were stationed in the Bone Castle, could effectively contain the Cloudflow people. If the Cloudflow's fleet could be extirpated in one move, then it would not even be necessary to use these fifty-thousand troops.
Lex's main forces possessed high offensive power and had many cavalrymen. In this wilderness, the offensive power of Saleen's army would be inferior to Lex's. Saleen had brought along a camp's worth of new equipment. Even if his first camp paled in comparison to Lex's people this inadequacy could be compensated using equipment.