My question is: can an Assault, an Apothecary or a Techmarine wear a Terminator Armour? If yes, can they bear their standard equipment with it? I mean: the Jump Pack, the Servo-Arm, the Narthecium, the Reductor, special pattern helmets (like Fenris Pattern for Space Wolves or the Diagnostor Helmet for Apothecaries) and other things like these.

I'd handle much of this on a case by case basis, based on what models are seen using in tabletop.

Jump packs would not be allowed, as terminator just can't fit that pack/they're usually seen teleporting in.

Narthecium I would allow, as GK paladins equip it.

Servo-harness/arms I would not allow, given there is no tech priest specific Tactical Dreadnought Armour (perhaps as a relic type gear, but it should cost more).

As far as helmets go.... thats a bit more difficult, as those armour pieces have specific armour values assigned to them. I might allow both though.

Lexnoctis said:

My general guideline as a GM personally is that I'll try to work out anything that exists on the tabletop into Deathwatch if its for the appropriate chapter. You have to remember that common sense doesn't necessarily play into what actually happens in the grim darkness of the future. It may make sense to outfit every marine with the best weapons available but the "reality" (if you can use that word about a fictional scifi setting) is that, despite having meltas and plasmas just sitting there, marines don't get to use them unless they meet the renown and req requirements. That said, I'd allow apothecary gear for a blood angel or grey knight in terminator armor similar to how space wolves and ultramarines get their respective chapter specific gear (wolf helms and the ROB hesh or something bolter)... but not for other chapters as those are specific to a individual chapters. Jump packs fit on top of the standard power armor which doesn't exist on terminator armor so no go there (also meets my "no tabletop equivalent" rule) and the same is true of servo arms. The general rule anyways with techmarines is that they seem to prefer artificer armor (I can't think of a single tabletop ruleset where a techie can get termie armor); if anyone wouldn't want to break with tradition regarding the proper use of technology, it would be the techmarine. While I don't find it game breaking, technically the fenris wolfhelms and diagnoster helms are for power armor and not terminator armor... but I don't see any problem with you as a GM coming up with a termie variant for some additional req points. In the end, allowing any of the above isn't going to break the game but may reduce the uniqueness of certain chapters and their specific wargear.