>>96229107
Baal isn't one deathworld, its three.

Baal is a giant earth orbitted by two moons, no normal humans live on Baal proper, just its moons which are called primus and secundus.

Baal has always been a shithole but its moons used to be garden worlds, during old night both moons got shelled to shit with atomics and covered in hostile bio weapons.

All the Space marine military infrastructure of the Baal system is traditionally set up on Baal proper while Primus and Secundus get to stay in a post apocalyptic hellscape.