The leviathan "Pride of Ollanius" was allocated to serve alongside the 22nd Army Group on their formation. A venerable relic, "The Pride" is currently assigned to the 9th Necromundan regimental command.
While some members of the 22nd's command structure were opposed to letting the Necromundans have access to such an honoured war machine, the Necromundans themselves are not afraid to commit "The Pride" to battle whenever overwhelming firepower and a statement kill is the best option.
So I need to come clean here.
This Leviathan isn't actually mine, it's just in my possession at the moment. I consider myself the current custodian, similar to how the Imperial Guard officer in command of it would be. Just as the Leviathan would belong to the Adeptus Mechanicus or the Imperial Army as a whole rather than the regiment using it, this model belongs to a mate of mine who asked me to paint it for him an age ago, around the time when life got busy and things other than toy soldiers took over.
Just as it is a venerable old relic in the grim dark future of the 41st millennium, so too is the model. Circa 1990, it is a satisfyingly heavy chunk of lead that was long out of production well before the game it was built for was long out of production. With some nice details and a stupidly big gun it fits in well with my Epic Imperial Guard army.
It was quite a straightforward paint job. I kept it fairly pristine, without any battle damage, as I figured that it is newly assigned to the newly raised regiment. Plus it isn't mine, and I didn't want to go messing it up and painting on heaps of detail if my mate gets back into the hobby and wants it stripped and given back!