Hornyninja stated that there was a miscalculation...he wanted her invincible to instant KO attacks and instead made her invincible...but I think he uploaded a fix for that a while ago
if you mean insanely hard than yes... it's theoretical possible to beat him...but story wise you'll loose anyway.
to "win" you have to beat the original AND all enemies on the field
...did the king or one of his copies already consume a slave to heal?
I think hornyninja said that he wanted to make them killable after the first succesfull heal
Game was Updated to Version 0.8.2
The fight with the Lust king got an overhaul makeing the seemingly endless battles void... he'll be a bit harder to deal with as he is more resistant to stun lock tactics (he can still get shackle bound...it just won't last that long).
Also a new chapter with Amelia makeing a jailbreak and Sebastian visiting Rakshivahs home...in a rather violent manner