One thing worth noting is that Empress is much more difficult to manage in multiplayer. It’s a lot harder to predict the boss’s attacks when she’s constantly switching targets and you can also get hit by offscreen projectiles.
The daytime fight will actually be easier if you fight it one at a time, since a single slipup will end the fight. I’d choose whichever player has the most experience with the boss to kill daytime Empress, or if you’re all newer, you can take turns.
Anyway, if you’re fighting the Empress, you should have full Hallowed armor, a Brain of Confusion, and a Black Belt or Master Ninja Gear. These all offer dodge chance, which are the only way to survive hits from daytime Empress.
You also want either Betsy, Fishron or Empress wings (although all of those are hard to get, you can probably pass with Spooky, Black Fairy or Christmas Wings), a form of dash such as Master Ninja Gear, Soaring Insignia, and a Gelatinous Pillion to fall quickly.
Ranger can probably pull more with a Tsunami than the Chain Gun. A Tsunami with Holy Arrows will offer some of the highest DPS of any pre-lunar ranged weapon. Mage’s weapon looks fine. You’re super far behind in gear - you definitely want to get a Xeno Staff and Kaleidoscope before daytime Empress.
