The entire concept of this bossfight is simply to make the encounter as tedious and cumbersome as possible. I understand that you're fighting a tank that has its own army of protectors, but every aspect of the fight just exudes passivity.
If you stand a couple of meters away from Rom and his spiders, nothing will ever happen. They will never attack. They just skitter around and never attack. It perfectly mirrors the tedium of the whole encounter.

Just get behind the spiders with a Kirkhammer +10 hammer smash and one-shot them one by one. Then likewise on Rom, but with charged R2 smashes. Just gotta be patient and methodical!

I was fighting the Lower Pthumeru Chalice version and it started to constantly spam it arcane projectiles, so I hid behind a column until it stopped. After a while it didn't cast anymore arcane attacks, had run out of manna / MP (?) Not sure if it was a bug or not.

Yo....f*** this boss.

how the hell was this thing once a women

Try thunder but also, stunlock

i hope everybody who was involved with developing this boss gets curb stomped

Holy ****ing **** shes a mealy bug

My biggest problem with this boss is that it's entirely a test of patience which means that it's incredibly tedious. The first form is fairly easy, but still can take a while because you have to take your time killing the dozen spiders she summons. In all of the following rounds you either have to take your time killing the spiders while avoiding overpowered death missiles (which takes forever and is basically the game just wasting the player's time) or try to deal enough damage on the first round and try to dodge past the spiders to kill her when she reappears. If you try to use the first strategy, the boss instantly stops being fun as soon as you have to try a second time because of how ****ing tedious it is. The second strategy is slightly more bearable, but still remains fairly tedious due to the need to kill the spiders in the first round. The only exception is if you have enough DPS to kill her before she can start any of the later rounds because at least then you win the first time and it doesn't have time to become too awful.

Rom, the Vacuous ******* is the dumbest possible boss to put in a cramped chalice boss room. Ripping my hair out fighting this f***er.