When I was creating my initial Cauldron deck, this is a version I did some test runs with. It was very consistent and a ton of fun. It's pretty much just recycling Reaper and Vara, the rest of the deck is just made to support the purpose by giving you tons of draws and discard options. Also, Grasp Scourge on turn 5 and you're set.
Big Feln Cauldron https://eternalwarcry.com/decks/details/AzXdJKONmO8/big-feln-cauldron
Big Feln https://eternalwarcry.com/decks/details/5SmAWDrMjcw/big-feln