This is the Neviilz Priest of the Feast Deck w Yogg he was playing on 
stream at high legend on NA. In search of the ‘Unicorn’ Priest deck I’ve seen a few decks being played at high legend since the release of Priest of the Feast from the One Night in Karazhan adventure.
It’s a better card than people thought before play testing it. It’s not META breaking by any means, but in the right deck the healing really makes a difference.
This is a control deck. Look to remove your opponent’s threats with cost-effective spells. Use Priest of the Feast to heal, and Wild Pyromancer to get board clears. Put your faith in Yogg when you’ve cast 10+ spells, or you have no other option.