As per the errata rules a tech-priest is allowed a number of mechadendrites equal to his/her toughness bonus. The Ballistic and Manipulator ones can only be attached to the shoulder, the Medicae and Optical ones can be attached to either the shoulder or the sternum, and the Utility Mechadendrite can apparently be attached to any suitable location. And as far as I can tell, there are no other mechadendrites. Even tech-priests with a starting toughness below 35 can reach a bonus of 5, and can therefore,eventually, have all five mechadendrites, but is that really possible? It falls on whether you can have one or two mechadendrites attached to the sternum, and I'd say one, but I suppose it depends on what the connection looks like. Every image seem to be of shoulder-mounted versions of all five mechadendrites though, so that's not a big help.

Has this come up in anyone else's sessions, and if so, how did you deal with it? Allow for only four mechadendrites to be attached at any one time, allow for two sternum placed mechadendrites, or some other method? Thoughts from everyone else is naturally also welcome!

Just leave it up to the tech-priest player to describe. The rules say he is entitled to his X mechadendrites (though to be honest, I'd just remove the limit - it's not like he can't spend the thrones elsewhere), so that's what he can get. If he says that for example his optical mechadendrite is integrated into his ballistic one so he can see where he aims the gun or it's an eyestalk extendable from his real eye, more power to him.

I've been wondering why only Tech-priests can get mechadendrites. I have seen numerous 40K pictures that have individuals with mechadendrites and they where not necessarily tech-priests.

Salcor

Hereteks?! XD

I think you should let them go with it if they can think of a logical or roleplaying reason.

I don't find any reason that disallow tech-priests to mount more than one mechdendrite on, for example, shoulder. So I think it's all correct with it.

Mystificator said:

Just going by the pictures of the different mechadendrites (which should be an accurate depiction of a common version) it does not look like there is enough room on your shoulder for more than one; they do look like they encompass a shoulder guard/pad that leaves little, if anything, of the shoulder exposed. You'd have to have unbelievably broad shoulder to have room for e.g. a Manipulator and a Ballistic on the same one. But maybe I'm just overanalyzing the issue.

Soooo... you'd have to be a feral world strapping build, and a tech priest, probably with the bulging biceps (Or triceps) talent to carry more than one on your shoulder. NO FERAL WORLD TECH PRIESTS! BLASPHEMY!!!!!

BloodAngelAzrael said:

Well going by the size shown in the pictures it would almost seem like it.

Considering how a techpriest's potentia coil can be both light-weight and high-tech or low-tech and hunchback-inducing, I fail to see why this wouldn't be the same with other implants. Also, why wouldn't one simply integrate two "shoulderpads" into one?

Cifer said:

True, as I said: maybe I'm overanalyzing the issue. I'm guessing mechadendrites really become like arms and legs for tech-priests and can coordinate them accordingly, that is prevent them from clashing and becoming intertwined. I'd just like to have more info on how mechadendrites are integrated, and I can't seem to find anything truly substantial. Maybe the future of Dark Heresy has an Adeptus Mechanicus book in it.

"Arms and legs" sounds like the right analogy here, especially since modern day humanity is right on the way to functioning cybernetic implants - in animal tests, monkeys were already able to use a robotic arm with pretty good dexterity. The problem right now is more along the lines of rejection instead of control.