I'll purge them with a thousand wraithcannons. Then they can test the mettle of their faith in the warp.
That's actually the right idea! Pity there's an Inquisitorial fleet behind the nearest moon, with a Grey Knight Strike Cruiser, just waiting for your fleet to turn up. How else did you think the Sororitas got there? Oh look Teleport Flares! I expect your fleet knows about the Grey Knights now.
Be it Chaos or the Imperium that planet is getting nuked by one of them one way or the other Oh look our Brother Knights have Sister blood to protect thy aegis from said Chaos fleet, this story has many convenient plot points
*The Chaos Fleet meets the Inquisitorial Fleet and Grey Knight cruiser in full frontal assault..... and actually do serious damage* *It appears a mostly even stalemate, but the Chaos side is clearly winning, slowly but surely, ship by ship* If there's a fleet here, we will meet them in combat. Simple as that.
STOP...... WASTING.... TIME!!!! *Begins to teleport ship to ship of both fleets. Sabotaging generators to explode after letting the heretical planet's gravity pull the ships in.* Im sorry but I can't let them live..... IT IS BETTER TO DIE FOR THE LULZ THAN TO LIVE FOR YOURSELF!!!