‘The Doctor Dances’ had its own nano cloud spread infection creating gas-masked zombies. The shambling animated corpses in ‘The Curse of Fenric’ have more in common with zombies than vampires. The Daleks also made use of a form of zombie in the 5th Doctor audio ‘Plague of the Daleks’
‘Asylum of the Daleks’ introduces the idea that the Daleks can now bring the dead back to a form of life, turning them into weapons. This is a very scary idea that can make for a very tense horror based adventure.
We can assume that the amount of memories the zombie puppet has access to depends on their level of degeneration. Harvey, who was preserved in the cold outside, has enough memories to pretend to be human. It is unlikely the corpses inside the escape pod would have the same level of memory.
In these circumstances it is very likely that the nano cloud installs basic programming. Zombie puppets can move, follow their Dalek imperatives and solve basic problems. They have enough understanding to taunt their prey.
Zombie puppets are scary because in theory they can’t be killed. Only by destroying the body completely could you be sure that you were safe. If you wish to keep to the zombie template then their head could still house their computing power, destroying the brain effectively shutting them down.
Unlike most zombies these are also capable of ranged attacks, fitted with extermination beams. When attacking as a horde it would make sense for the zombie puppets not to make use of this weapon, for fear of hitting one of their own and reducing their effectiveness.
In environments where the nano cloud isn’t air-borne the zombies themselves may be the source of infection. Their lungs could house nano cloud factories, releasing the infection into the air around them. It could also spread by touch or need to be injected into the victims blood stream, forcing the PCs to avoid being bitten or scratched.
It would appear that when not responding to intruders zombie puppets are inactive. This means that PCs should beware any corpses they find. They never know when they might suddenly rise and attack.
We don’t know just how extreme an environment the zombie puppets can survive in. The Doctor and Amy are able to use a fire extinguisher to force Harvey back but is very likely that a zombie puppet doesn’t need to breath.
If this is true then they could be found deep underwater or in the the depths of space. They could wait under sandy dunes, radioactive wastelands or within frozens wastes. No where would be safe from their reach.
The great advantage of the zombie puppets is the sheer amount of raw material available for the Daleks to create an army. Raising a planets dead could be a terrifying way to start an invasion.
An adventure could begin with the PCs being amongst the locals of a planet or particular time period when zombies start to emerge. The PCs will have to initially survive the chaos before seeking out their origins.
During this period you can follow the format of popular zombie fiction. Survivors are often their own worse enemy. Fights over diminishing resources and those try to grab power can leave the survivors vulnerable to attacks from the undead.
Over night a planet’s infrastructure can breakdown. This could have a huge impact on hi-tech planets, where the population have never had to do the simplest of tasks themselves. In addition technology might be the only thing keeping a planet habitable and when systems begin to fail the environment becomes another danger.
It will seem incredibly bleak for the PCs, having survived the ever increasing waves of zombie hordes, to find out that all of this is just a prelude to a Dalek invasion. Could they help the local reorganise and fight off the Daleks?
The Daleks might see the tactical advantage of seeking out worlds or regions of space locked in conflict. Not only would their prey be distracted the freshly killed would make better zombie puppets than older corpses. A good opportunity for those at war to put aside their differences and unite against a common enemy.
No longer would the Daleks need to keep people alive in order to obtain information. They can kill subjects and bring them back later, extracting the data directly from their brains. Resistance fighters would have to destroy the bodies of their fallen allies to avoid them being converted.
In a campaign the death of an villain might not be the end. PCs might encounter them in the future, now a zombie puppet. If they are well preserved then they might be little different to how they were in life, aside from their new alliance to the Daleks.
Even allies might be converted in this manner. This could be a huge psychological blow for the PCs, being forced to face a friend who they lost raised from the grave and now working for the enemy.
To give your PC’s hope there are many ways that zombie puppets could be defeated. Despite appearances they aren’t as intelligent as they were in life. This can allow PCs to lead them into traps or ambushes where their bodies can be destroyed.
Their artificial nature may make them vulnerable to electricity. A sufficient charge might not destroy the body but will render the nanobots and their internal systems inoperative. The good thing about electricity is that it can be conducted, especially if the target is standing on metal or in water.
Technical minded PCs might attempt to reprogram the nanobots or create their own cloud that deactives the nanobots within the zombie puppets. In effect they create a cure that could be spread throughout the zombies or even turn them on each other.
It is stated that the nano cloud only affects organics so PCs could seek alliances with robotic races. This might be especially good for an adventure based around a robot underclass, allowing these oppressed automatons to save their creators and thus prove their worth.