Ghostkeel reactions

By the pontoons!’ shouted Enrod.
Farren shouldered his rifle and took a shot. A heartbeat later his squad followed suit, a dozen killing rounds searing through the rain.
The volley of bolts was met by tiny glowing motes, a storm of fireflies that flickered into life to collide with the self-propelled rounds. They detonated the projectiles well before they could strike their target. A chain of explosions flashed in the rain, and orange light caught the edges of the warsuit’s massive bulk.
The battle engine was far bigger than a Primaris Marine. Bigger even than a Redemptor Dreadnought, come to that, and yet it was rendered all but invisible by its camo field.
...
Sergeant Orenst and his squadmates had finally made the gantry, levelling their bolt rifles and sending a tight volley into the rain. Once more, a swarm of intercepting firefly-things appeared from nowhere to meet them. The bolts lit up the night once more, their wrath as futile as the rain itself.
...
Another ball of plasma hurtled towards them. This time Moricani and his team were ready, sending a volley of their own superheated energies from their plasma incinerators to blaze straight into the incoming shot. Farren heard Moricani laugh harshly as the air turned to spectacular inferno. His autosenses kicked in, dimming his lenses to keep him from being blinded entirely.
‘Now!’
Spinning around on the spot like a Medusan hammer thrower, Thrunn whirled the heavy iron drum before releasing it with a roar. Farren knelt and took a bead as it curved through the air towards the site of the stealther’s plasma discharge.
‘Maximum yield, brothers,’ said Moricani. ‘And make ready.’ Farren heard the telltale whine of the plasma guns reaching their highest output; a lethal risk in any situation, even for those as scrupulous in their maintenance rituals as the Hellblasters.
‘On my mark…’ said Farren. He mouthed a silent prayer to the Omnissiah, running his index finger along his gun’s barrel to calm its machine-spirit.
His bolt rifle bucked as he took the shot. It struck the promethium barrel dead centre, the armour-piercing bolt punching straight through.
With a deafening crack, the promethium vapour ignited and the barrel came apart in a puff of flame. Splintered wedges of metal burned in all directions. Once more the firefly countermeasures of the xenos stealther shot out, this time flitting to intercept the knives of shrapnel coming towards it. Illuminated by the flame of the detonation, the colossal warsuit had been made visible, a giant of smooth lines and glinting sensors.
‘Fire!’ said Farren.

War of Secrets