Ixion was the first and hardest Ragnarok we've had to date. It required the right composition and precise overdrive timing. With maxed teams it'll probably be more doable, but those without (Joan or Gaia) + Black Propaganda (Mordred) are likely screwed. Ixion is susceptible to Charm, so Mordred *might* work in a pinch, but a combination of Joan and Gaia will be most effective.