You should use full frenzy equipment + tempest rage. Maybe, you will get overheat in your attack. But If you really bad in attacks, try Damage Return and Frenzy + Tempest Rage. Maybe It will work.
Free player here, I just beat Eclipse May after months of trying (and Titan quickly after) with the following:
All items lvl 52 with the Tempest Rage enchantment
Knuckles, Frenzy
Amor, Damage absorption
Helmet, regeneration (although this was pretty useless – would’ve changed it if I could afford it)
Force wave, Poison
Needles, Frenzy
(and yes it was a ridiculous amount of grinding to get to that.)
After months of trying, I realised that I needed to change my perks to tailor them more to the attack speed of the knuckles’ attack. I focused in particular on Desperate and Furious, then Avenger, Block Breaker, Enlightenment and Pain Rage – and had to take a few others I had little use for... everything that could give me +% damage in addition to Frenzy and the Tempest attack.
35 gems to reset perks is a lot more affordable than paying 500 for the chain sword – just watch a lot of ad videos while you’re busy with other stuff and you’ll get there. Don’t spend gems on prophecies in the Underworld, or on the Ascension.
Attack May constantly, the knuckles’ double attack is effective for this (but also use other attacks, the low punch is good to create the right distance for a double attack).
Use the needles if she uses the smoke invisibility (good chance of a critical which makes her visible again), and be prepared to roll away when she uses the ring of fire magic. (or hope your armor absorbs it). And then it’s a matter of being lucky and getting a head hit with Furious, Frenzy, Tempest and/or Desperate / avenger / pain rage on top – enough damage to take her out and prevent her insane regeneration enchantments to take effect. This will take some attempts to do, since she’ll easily drop you in one or two hits.
For the second round, just hit her enough that she won’t absorb all of your attacks and wear her down.
For me it was really resetting my perks that made the difference. Hope this helps.