It's pretty easy to get good fighters. You can, with a little bit of patience, get 12/13 million in a gold prize fight even with mediocre fighters - I think I was around level 30 when I could do this easily - and then you'll have a whole arsenal of strong fighters. I earned my Primed from this, and even before making her a diamond, she was incredibly strong and was an easy counter to Bio. She deals a lot of damage with her Napalm Shot alone, which, as I previously mentioned, can interrupt her charging. Peacock also has movesets like this. Really, it is a matter of changing tactics. If you really hate Parasoul or Peacock for some reason, then characters like Double, Ms Fortune, or Squigly have the chance to inflict hex/death mark. Red Velvet Eliza can inflict Hex reliably, if you have her. Wulfsbane has Heal Block, and again, you can earn him from a prize fight. In Rift Boss specifically, there's plenty of fighters such as Harlequin, Primed, Sheltered, Toad Warrior, Ultraviolent, etc. that deal enough raw damage to deal with her. I agree that Bio can be annoying, but any good defense team should be.