First thing to note: Rom is the most broken chalice dungeon boss. You're probably better off farming OOS Nourishing from Isz Amygdala or settling for the gems dropped by the gargoyle on layer 2 of pwmf22gu. That said....
This strategy works for just about any pure physical weapon (not blood or elemental) and works best with heavier weapons that can stagger Rom, such as Whirly, Kirk, or Ludwig's, or weapons with very high dps (such as saws). Combine it with Poorman's gems and you can kill this boss very very quickly.
YOU DO NOT HAVE TO BE HIGH LEVEL FOR THIS. IF YOU HAVE TROUBLE WITH THIS STRATEGY, IT'S LIKELY THAT YOU NEED TO USE:
1) BETTER GEMS (I RECOMMEND TEMPERING OR POORMAN'S)
2) A DIFFERENT WEAPON
3) A SLIGHTLY DIFFERENT ATTACKING STYLE (SPAMMING BLINDLY DOES NOT ALWAYS WORK)
The spiders can and will OHKO you if you're not careful. So will Rom.
![](https://i.ytimg.com/vi/u2ep58qVDz4/maxresdefault.jpg)