Gotta love them, big strong, have Fawesome weapons.... wait what? This thread is to know how to kill them? YOU BASTARDS!!!! *poked by a shotgun*
Ahem, yes well these guys are really hard to kill. The best way honestly is to get into combat. The Farseer and the Warlock can't protect them for long
... *sighs*. The powerfist would eat up these guys in a jiffy. Even though they have a higher S then a marine, and a good T for a Elite/Troop, they still only get 1 attack each. And the warlock too, but it's nothing dangerous.
While shooting, anything with a good S + AP level and distance should take them out, eventually. Plasmas would do wonders against these guys, whether it's an in-your-face plasma pistol, rapid firing plasma gun or a template plasma cannon. Generally, anything single shotted could do something, but if the Wraithguard player had a warlock and farseer(and had any idea what he's doing with them), chances are your not going to get them that much.
And yes shaso, if your playing Wriathguard, you be an idiot NOT to take a warlock. Not nessessary for the conceal power, but the auto pass for the Wriathsight test (and in Iyanden Eldar, it's nessessary to have a spiritseer