Thanks for playing the game and taking the time to leave a comment. It's cool to see that you were able to build a nice synergy using bonus card pool from an event.
Regarding The Son enemy enemy I agree it is probably quite easy even containing the full moveset - which I think in this build/version of the game two abilities are missing some functionality. The turn that adds a Salt card also applies another trap card Burn (which applies stacks of burning to the player if in hand during at the end of turn), and the other non-attacking turn purges some amount of negative status effects and gives him stat buffs. Despite this, the enemy still feels easier than some of the earlier swarms, so balancing is certainly something that needs a lot of work.
There is a actually a bug when it comes to cards which draw cards in that a card can draw itself when played, this means that infinites which should require at least two cards to cycle are actually possible to do with just one zero cost card (oops). But your combo sounds great. I am working on rebuilding the game from scratch top down to address this major bug.
Last Embers is definitely a strong card, even more so when discovered via the Fan of Flame. I could see some part of it being nerfed in future, e.g. the card draw. Righteous Nova from the Warrior card pool is definitely on the list too!