FWIW, I was able to get five wins with ~17k total stats using Natasha and Cronus, but it also took Aftershocks, double blasters, judicious use of potions, and like a hundred losses.

(Speaking of blasting, , maybe mention it in the guide, at least for the later stages? Yes, it's covered in the general guides linked at the beginning, and it may seem like it goes without saying, but if you're pitching to non-hardcore battlers I think it's important enough to repeat.)

I forgot to mention this yesterday, but my T12 with a little over 16k stats relied heavily on boosting. I was using Cronus and tkss as main weapons since his def>str. He also has 7k HP so the 12% heal really helped cushion the blows. Scrolls were a bunch of fatal fire to cover fire block, gotf scrolls and rage of the paranesia.

The guide will mention a bunch of weapons that could be used based on the Hydra's weapons, but it also comes down to your pet's build and your strategy as to which weapons are the best to use.

Long live dual blockers. I wish there were more of them 😢

Added your note about blasters to the OP and reworked the fourth hydra's section now that its weapon info has been fixed.