Are these sentences worded properly?

FYI- The Council's legions are the southerners, and Aoth and the Griffon Legion are part of that army. Meanwhile, undead kraken-like behemoths emerged from the ground behind the Council’s legions and proceeded to massacre the southern troops. Strengthened by the creatures that had emerged with the premature night, Szass Tam’s army counterattacked ferociously and started to drive the zulkirs’ forces back. Also at that time, the legions of Lapendrar arrived on the battlefield and moved to assault the Council’s host, but Aoth and the Griffon Legion hastily engaged them.