I'm not gonna sugarcoat it, this one's literally just ultrakill, begging you @viral eagle, GIVE US VR VOXELKILL, RAAAAH.
Anyways, the caestus, it's always on your nondominant hand, pretty much just your hand but you can punch and use it to parry projectiles.
As for the G.C? it's a steampunk revolver, it can shoot up to 6 times before needing you to reload, maybe something similar to how pavlov's revolver system works. (flick back to eject shells, load in new ones, flick your wrist to the side to slam the cylinder back in.)
Now, let's get to the good part.
You and I both know what I'm suggesting, ricoshots.
Yep, using one coin per throw (not sure how you'd get the coins though, maybe a pouch on your hip with your offhand.), you can throw up to four, to do the following:
Shoot the coin, adds 1.5x damage for each coin chained, targets nearest enemy.
Punch the coin, targest nearest enemy.
Throw it at enemy projectiles for a chargeback, basically fancier parrying. (Also could comedically work on the skulls.)
Or just waste your money.
ITEM SYNERGIES
Forge embers, your caestus loses its parrying ability, but can punch way harder.
Silk chain, your caestus, when punching at an enemy, can pull light, or unrooted (things that aren't plants like slimes or wights) to you, or you to rooted/heavy things (plants, armored wights, etc)
Velvet purse, there is no longer a limit to how many coins you can throw, but the chain damage is reduced to .2x