Yes, the undying deck is cannon. Every piece here is undying invoked; except for the revived gate (it's mirroring which is summoning another one of it at 1/1).
Well, with this deck you can revive up to 3 times. This deck is hard to build and requires so much luck.
Tips for beginners:
You have to rush your faiths with the "on death: gives 2 faiths". DONT buy the "at start: gives faith", he's trash. Try to save as much faiths as you can while playing safe. Until 14 faiths, you can now get some high-tier cards. The point is that you need to grab some high-tier cards to decide which path you follow: whether its summoner path or copy-chaser or multiple-attack or health-buffer, it's up to you. Have fun with the game.