Can 2H wield a shield?

Khaso

I'm guessing they can't, but asking just in case.
Also out of curiosities' sake, if they can't wield a normal shield, can they use the Artefact Shield?

Klendathu

No and no. There is a paragon that can be added to artefact armour which has the same damage mitigation chance as the shield, though without the damage reduction of the shield.

Antonius

They can wield a shield (unlike Blademaster, which is mechanically restricted from even wielding one, I think), but not at the same time as wielding a two-handed weapon (and you can't change what you're wielding off balance) so you can't benefit from the shield while attacking. You could still wield one when not attacking for the added physical damage reduction, though.