Ship Destruction Planets (aka DEATH WORLDS)

Deathworlds. Yes. But not like in WH40K... I'm feeling like too much of my stuff is contrived as it is.

Nay, for a deathworld in the world of the CHG is one intended for killing things that get within a certain range of it. It has a single gargantuan death laser for melting any planets the LIR tries to colonize too close to the CHG and is then covered in endless turrets that destroy any unauthorized (and that's authorized by the CHG) ships that get too close (and "too close" basically means being within 5 light-years of them). There are then tonnes upon tonnes of robotiks underneath and on the surface of the planet who deal with anyone who actually manages to land on the planet and repair damage to the deathworld. They've also got ships so that they can directly engage LIR forces if they manage to get past the deathworld and head towards the parts of the CHG where people actually live (the CHG being able to construct planets has led to them liking to put as many as possible of them in as few, all near to one another, solar systems as possible for ease of travel and defense) to slow them down. These ships are also brilliant for setting up mining and plasma extraction bases so that material can be gained to put to use in repairing or even upgrading the deathworld. The robotniks have heat and magnetic vision at the same time as the planets being deliberately covered in fog so that living ground forces are less effective.

So far, 73 death worlds have been built and the CHG has been moving them around with gravity nets and portals to form a defensive line between the CHG and LIR. The CHG definitely intends to make more of these as they've stopped making habitation worlds (of which there are plenty anyway... at least until the The Population Program and some of its consequences kicks in) and has plans to create a line going from one side of the Orion Arm to the other, making it impossible for the LIR to expand further up. Any LIR colonies past this line will probably be taken out or conquered by the CHG.

As for their effectiveness: the LIR has only managed to destroy 4 so far and on each of those occasions they had to bring tonnes of firepower and get their best strategists on it but still needed several years and suffered tonnes of losses taking out each death world. In other words: if the LIR tried to take out all of the death worlds, it would lose 2% of its military BUT it would also lose a lot more and probably fall into (a bigger) civil war as soldiers and their generals don't want to be sent to die like that.