Horus'll be fine. Meanwhile, you can't allow the attack to stop. Even if you'd win, a long, tiring clash wouldn't be worth it. The army has to regain it's momentum.
You grab a fallen company standard from a dying warrior and raise it up as high as you can, hovering above the battlelines. You look around for a horn as well, but see none nearby. After a while, some of the warriors spot the banner and begin roaring their warcries and company chants. The mass of warriors begins to shift and move as men of different companies and forces form up and attempt to get to the banner.
Unfortunately, being so high above the combat makes you an ideal target for the Council Lightbringers as well. Silvery bolts of light impact against your skull, sending you spinning back to the ground. Again, hitting the ground hurts more than the actual bolts. While they do throw you around, it seems they're not very effective otherwise.
You leap back up high into the air, spinning the company standard in a wide arc like a quarterstaff. Another bolt flashes past you, breaking into a tiny lake of silver upon hitting the floor below. You spot your opponent, standing in a group of Lightbringers on the above floor and firing through the collapsed ceiling.
You aim and let the company standard fly. It races through the air like a bolt of lightning, towards the unmoving Lightbringers. Your target finally raises it's arms in hopes it would somehow help, but it's already way too late. The metal pole finds it's mark, and the Lightbringer's jaw disappears in satisfying crack of bone. Only after the creature falls you realize there's no reclaiming the standard.
Thankfully, it matters little now. The mass of warriors is pushing forward, sweeping down the remaining defenders by sheer force of numbers. You dive down and begin following the horde. You spare a quick glance at Horus. The wargod is hacking apart the warmachine's torso with visible glee, though his somewhat slow movements betray his wounds, or atleast his fatigue.
The two other Soul Engines are both cutting into separate splinter groups of the main army. While they are trying to fight back, it seems clear they're wavering. You consider attempting to capture one of the things, but that would most likely slow down the attack once again. Perhaps you can study their bodies.
You fly down to the head of the horde and direct them at the nearest Soul Engine down the corridor. The horde gains a sudden increase in speed upon seeing the enemy. A golden chariot comes down the corridor with incredible speed, pulled by invisible horses. An armoured pharaoh stands inside, lashing at the horses with his whip. You wince, seeing the spiked wheels of the chariot pull some of the Egyptian warriors down to be crushed by it's wheels while hurrying through the crowd.
The chariot hits the Soul Engine at full speed, physically ramming it half-way through the construct's leg. It roars in anger and falls to one knee. The pharaoh leaps from the chariot laughing, striking at the warmachine with his whip. It's soon snapped in half by the mouths, but the rest of the horde arrives at the exact same moment. The Engine quickly disappears below the mass of warriors. It takes down dozens with each strike of it's mighty blades, but sheer numbers soon overwhelm it.
While the mass of warriors attempts to finish the stubborn construct off, your thoughts turn to the Egyptian gods. You're doing their job up here. Perhaps it would be wise to go get some of them, even if that would mean the attack slowing down again.