"Enemy attack! On the flank! On the flank!"
The warning tore through the battlefield air over the Communications Channel.
Helios turned, his gaze sweeping across the darkness in a fraction of a second.
All he saw was a blurred outline, a slender black shadow racing through the shadows along the Webway's flank, heading straight for the Titan formation.
Even Helios, a Custodian Tribune, had almost failed to react.
The black shadow was too fast.
His senses had been enhanced to be many times sharper than a human's, and his reflexes honed through years of combat, but by the time he had fully locked onto and tracked the shadow, it had already crossed nearly half a kilometer.
Its speed carried the oppressive force of a Primarch charging at full tilt, and in some sense, might even have surpassed a Primarch.
An Adeptus Custodes warrior beside Helios tried to raise his Guardian Spear to intercept it, but the shadow gave him no time.
Like a shadow skimming over water, weightless and soundless, it left an afterimage behind and appeared at the Titans' flank.
The nearby mortal soldiers, and even the Space Marines, thought it was a ranged weapon fired by the enemy.
That was hardly surprising.
Judging by the naked eye and conventional sensory systems, the shadow's form perfectly matched the flight path of a large armor-piercing shell or some kind of superheavy projectile.
Its speed and straight trajectory were beyond anything a living creature could achieve. The first instinct of ordinary people and even augmented warriors was to classify it as some kind of bombardment.
Only when it reached the Titan's cockpit did they realize something was wrong, but by then it was too late.
The Black Sword's speed far exceeded anyone's imagination.
"The Kratos is down! Hammer of Dusk, fill