I know that the Slaugth are the masters of the long game and infilitration but even these tactics sometimes require a short burst of ultra violence.

So I was wondering whether any one had any suggestions on what weapons/bio constructions etc the Slaugth might use if they decided to go full tilt boogie and actually go to war in the Calixis Sector.

Essentially they are going to be one of the big bads in my Deathwatch campaign, there will of course be the necessary creeping horror and so forth that comes with the maggot men, but eventually the Imperial forces will realise they are isolated and then the xenos reveal their true nature.....

At this point I wanted the Slaugth to attack hard and fast to consume their enemies but I wondered what they might actually use, for example if they needed to take down marines tanks or even Titans?

I'd think that they are likely to attack from without with massive Tyranid-seize bioconstructs to soak up the brunt of Imperial firepower while they infiltrate Imperial forces and positions with their skilled infiltration and so cause havoc from within at the same time.

Maybe not something for Space Marines but a scenario for Imperial forces with being besieged from without by the Maggoth Men while they are also slowly killed off and eaten from within by infiltrators sounds rather scary.

Yes, that sounds like a good idea. I'm essentially running a joint Death Watch (primary story) and Dark Heresy story. Many of the Slaugth horror elements will of course be the focus of the Dark Heresy story arc with the Deathwatch being called in to the save the day later on.

I lime the idea of giant bio constructs with lethal maggot men kill teams striking from the shadows against the Imperial HQ and elite forces.

I think it might fit for the maggot men to have the xenos tech to reanimate forces possibly as well....

For a large-scale attack that could span both DW and DH , I could see the Slaught using humanoid bioconstructs that are designed to blend in to populations (shrouded in hooded cloaks to conceal their half-formed features) until the order is given to attack. Then, they swarm together and merge into a single colossal creature that goes on a hive-destroying rampage. Hence, the same monster could be used as easy-to-kill grunts that would create a mystery for DH Acolytes ("What are these infiltrator-things?"), and as mega-beasts that can challenge a DW Kill-Team ("It just stomped on Leonatus!").

What I wouldn't give to have another "Mark of the Xenos" style book, but with more in-house Xenos filth written up by the FFG team. It wouldn't hurt to include Hrud in there either.

What I would do is flesh out their background and get them to make sense.

Because as things stand they have no motivation for trying to take over or attack anything. Their whole point is that they want to eat sentient beings. That are already dead. They don't need to kill them, note. They are essentially no different from rats. The Imperium does exactly the same thing sometimes. The Slaugth in the DH GM's screen adventure were actually harming no one; they were just hanging out, having a BBQ with meat that was alreadt dead.

So what I would do is work out some sinister plan behind their dietary habits. They are devouring souls, perhaps.

Well what I'm going for is that they are essentially addicts. They intend to turn the sector into a grave pit/abattoir of destruction and war cut off from the rest of the galaxy while they pick over the remains of the human cattle. In fact I like the juxtaposition between their advanced technology and their very basic motivation of all consuming hunger. The other point that makes them somewhat different to Tyranids is that they could survive on regular food (in my opinion) but effectively choose to eat sentient creatures because they enjoy the emotional rush.

Precisely so. There's even an ascension adversary slaugth (Recusant) whose addiction has got out of hand and is no longer being subtle - directly attacking ships in transit, outposts, etc - and the rest of the Slaugth are getting worried that he's going to blow their long-running, subtle infiltration of the sector.