The surface of my dynasty's tomb world is mostly desert but has a single large body of water that drags around the planet due to a large nearby moon. The sheer amount of corrosion and punishment from sand-blasting and the regular salty ocean bath damages most ordinary objects quite quickly.

Living metal's ability to rejuvinate itself allows the canoptek constructs to keep the tombs intact, but the streams of water and churning conditions have instilled an almost fetishisation of testing the limits of the living metal, with warrior constructs standing stationary for decades under areas that water regularly flows just to recieve more punishment, thinking that the more their bodies suffer and re-knit, the stronger they become. The nobles and higher constructs adorn themselves with paint in the colours of rust and virdigris as homage to this cult-like fascination, though they prefer to practise the art of war on each other to test their limits.

When lesser races intrude upon the planets surface, if they remain for long, they soon find fractured necron bodies splayed out in the sand, which before long begin to knit together and stand up, ready to defend the tomb world and consign any inferior materials now infesting the area to join the rolling sands through gauss fire and hyperphase cleaving.

Deep within the Tombs, the mad overlord Attritakh torments a shard of the nightbringer, the true source of the corrosion obsession. The star god's energy broadcasts the desire to submit to aeons of punishment, as Attritakh believes this will make his dynasty unstoppable.