Self-preservation
Haowen Pass was not the only place under fire. Sanlujue Fort was in fact, not that far and rested upon the stretch of land, cut through by Liujue River. Not long ago, it was separated by Mount Wuhong's hulking figure but now it was vulnerable and was at risk at being overrun by demon forced.
For one reason or another, whether it was the surrounding geography or the internal turmoil that simmered within the Wandering Wolf Sect and the once almighty Wind Stone Temple, Sanlujue Fort was infamous for being poorly manned and supplied for countless of years. The fortress traded hands between opposing forces over and over again like the waxing and waning of the moon. By some miracle, the Wandering Wolf Sect or perhaps the remnants of the Wind Stone Temple had maintained control for roughly three years.
That was a long time, at least in Sanlujue terms.