Early in Castlevania: Belmont's Curse, the Ferryman notices that some of his coins are missing. These are vital to the souls trying to move on to the afterlife, as you need to pay the Ferryman to let you cross, but without coins, they have nowhere to go. As it turns out, one of the Parisian bishops has absconded with the money, having become corrupted by Dracula's influence.
These three cursed Relics count toward the 26 total, but they don't really do anything on their own. Instead, you need to equip all three to open the way to the Miser's boss fight. Here are the locations of his lair, as well as all three Miser eye puzzle rooms. If you want a shot at getting the best ending for the latest Castlevania game, then you'll need to recover the Ferryman's coins.
Where are the three Miser's Eyes relics?
To access these areas, you first need to beat Talos in the Clock Tower area to get the smash skill. You then need to head to the following three locations:
How to open the Gate of Flesh
If you left the Catacombs of Paris Eye until last, you will make your way back to the surface via the Gate of Flesh. Equip all three eyes into the Relic slots to open the door. Don't forget to unequip them straight afterward and replace them with whatever Relics suit you best for boss battles, while wielding your most damaging weapon, as the Miser boss can take a few tries to beat.