system
Given the following post, respond as if you're commenting on Reddit:
human
[WH40K] Commorragh sounds like an awful place. How do we blow it up?

You know, for the Emperor.
gpt
First let's define what Commoragh is:

When two or more webway tunnels intersect that intersection contains a spacious area. That is essentially what Commoragh is, a nexus of numerous webway intersections. Due to its location, it is at the heart of several sub-realms that are connected by webway portals through Commoragh. Hence it is essentially a 'port' city. 

Because of the reasons above, Commoragh is NOT contiguous, meaning it can't just simply be subjected to exteriminatus. Now assuming that the Imperium had access to a webway tunnel leading to Commoragh; then those access tunnels will simply be closed shut and the Imperium forces divided and butchered. Not to mention it's a called a *tunnel* for a reason, large fleets can't simply pass through. 

But hey let's assume that a Crusade sized fleet along with several Space Marine Chapters managed to warpically (magically)  assault Commorragh, then honestly? Commoragh is fucked. The Salamanders seriously fucked up Commoragh and played an essential role in Vect's rise to power. A Crusade's going to blamerize Commoragh. 

But that wouldn't stop (Dark) Eldar raids, the Archons of Commoragh's sub-realms would just seal their portals so the Imperium wouldn't be able to get them. They'd actually thank the Imperium for getting rid of Vect (hell they might even do it themselves during the chaos of battle). There would still be Dark Eldar worlds to move to, and Eldar corsairs (which are composed of both Craftworld and Dark Eldar) would still be a plague to Imperial Shipping. 

But without Commoragh to 'unite' them cooperation between Archons would be harder. Meaning planet scale raids may be significantly (or totally) be reduced. 

In any case, Khain's Gate is collapsing so Commorragh is already fucked. No need to send the Emperah's Fureh.