Last Embers is by far the best card in the game as far as I can tell. Nevertheless, the game was fun. Beat it with a rogue focused on repeatedly using the Fan of Flames, skipping most discoveries other than Last Embers, Kunai Storm was also good, though taking damage at EoT from thorns on each attack card was an unfortunate surprise, given that the shields from ability cards don't seem to happen on EoT discards.
The Son attacking very infrequently made him much easier than normal combat encounters. I'm not sure if this is an AI issue-- he seemed to want to spend a turn crying salt every time I lit him on fire, which was like every other turn so that may have been the problem. Salt buildup could have been an issue, but incinerate is pretty common in the fan discoveries and I don't know how you would have a reliable source of fire damage without the fan-- everything else the rogue gets at least has expend.
Last embers+2xRummage+ Upgraded Sleight of Hand+Rogue's Shiv+Ace in the Sleeve+Incinerate is pretty much an infinite loop once your deck in small enough from expending cards.