Ziggurat 2

Shield bash is the ability of Nadja, unlocked for beating the 8th chapter of the campaign.

For clarity, a vanguard is one of those large green orky bois that carry a shield and like to rush at you with it.
The hardest part of this achievement is simply getting Nadja and finding one of them during a run, then its as simple as using your class ability and slamming into him. Its RNG when you get one but its trivial in its difficulty to pull off.

Happy hunting (>*_*)>