Yup... same here... just finished it.
Soulsap (BAM! 3000HP instantly gone) + blind = Dragon unable to do anything what-so-ever.
Add some Boulder Dash or Cripple for the 50% Bully bonus my melees had, add some summons to add to damage, and it's just punch-the-useless lizard. Handy of blind is that it also gives you 100% chance to hit the target.
But yeah, I guess it was odd Astarte did nothing except comment once-in-a-while, and there was no special music for the battle.
Guess I got lucky I had a Witch I guess though... didn't really figured out how powerful Soulsap until like 2 fights before that. Description made it sound horrible... Then I saw HP-reduction, damage reduction, -50 to saves and resistances, and even with 1 turn duration I could cast it each turn on my mage.