All that's part of the write-up, which I've been told busy DMs don't need because alignment tells them everything useful. By reading the description and learning useful information, you're obviating the need for the non-information alignment will give you.What's their role in the story? Do they have any motivation or goals? Because that still matters. What alignment tells me is a bit about how they might go about how they go about achieving their goals. It's not like I look at just the alignment, but alignment is a big part of it.
One of many horrifying byproducts of the poorly maintained magical waste depositories, hundmithanden are descended from stray dogs tainted by magics that permeate such places. The eldritch contamination has partially twisted their bodies into a quasi-humanoid forms and given them sapience.
This sapience is truly a curse to these wretched creatures because the transformation plunges them into a world of wholly alien concepts only half-understood coupled with lingering animal instincts that no longer fit their physiology. The result is that nearly ever hundmithanden is afflicted with enough wherewithal to curse their existence, but not enough to contain they fear and rage that consumes them.
From a distance, hundmithanden resemble large dogs, usually with long, curly fur ranging from brown to rust to black. Upon closer inspection, however, one will notice that the creature's front paws are painfully elongated into something resembling humanoid hands and their rear legs are over-long and the joints don't resemble those of a normal dog's. In their early days of transfiguration, the poor beasts clumsily lope along on all fours, but as their intellect progresses, they begin to walk upright and eventually begin to cloth themselves in whatever clothing they can find and wander the streets in thin human guise.
Hundmithanden, however hardly ever manage to focus on anything besides their envy and hatred for other sapient humanoids. They fixate on a single person or type of person at the time, stalking, plotting and eventually ambushing them, strangling them in their beds or in darkened alleyways. In this way, most hundmithanden quickly become brutal and prolific serial killers, haunting cities and towns until hunted down and slain.
Their canine cunning helps them elude capture, but their continually fracturing minds slowly cause them to devolve, becoming sloppy, and less careful.
Between kills, hundmithanden live as vagrants, foraging through trash, sleeping in out of the way places and avoiding human contact. If anyone disturbs them, however, they quickly become the object of the creature's obsession—their next victim.