The battle between high-end forces was intense and quite deadly. So it was expected for the weaker forces on both sides to move away from any place near these.
The high-end masters led by Sloth placed the mission of protecting other weaker masters in front of their eyes. But to the dark masters, this wasn't a thing to consider in the first place. That made them try to engage weaker masters in the ongoing battles, ending up with Sloth and others expanding the area of their fights, asking other masters to retreat and evacuate, and ending up forming isolated areas in the middle of the masters' army.
When new high-end enemies would pop up, Fang would interfere and keep them a little busy. Then others would come and shoulder the pressure off him, before taking them away from the area close to the gate.