You get Bloodshield rings as reward in CvC. They give shield to the attacker, what makes the Scarab quite easy.
If you don't have these Rings, you have to go the Metalshaper route. This champ has to be the fastest of your team. Otherwise, the other teammembers attack unshielded before he acts. You don't want the Scarab to have any turn in this fight, otherwise he strips the shields and can bring your champs into a provoke-counterattack-provoke-counterattack... trap and you are lost. You need champs that reduce the enemies turnmeter to prevent that, like Coldheart (you have that one) and Armiger. You should definetly build an Armiger for your account, that guy is, even as uncommen, better than most epics in the game.
Lots of great help, thank you. With MetalShaper, it's been suggested he needs to be fastest. Is this still true if I put shield gear on him?
I'll stop using my next Armiger as food and level him up. Thanks for this tip
Shield only lasts the first three turns. Thereafter, you'll need to rely on his shield move. Something else to keep in mind - I don't see him in your list, but if you have Miscreated Monster, he does the job except better.