Rare Ergo is a valuable item in the game Lies of P that can be traded for special weapons and amulets with Alidoro the Treasure Hunter. Here are some things to keep in mind when dealing with Rare Ergo:

• Rare Ergo is usually dropped from bosses you encounter across Krat, such as Champion Victor or the Kings Flame, Fuoco in Lies of P.
• You can consume Rare Ergo for 5,000 standard Ergo, but its generally recommended to hold onto them for trading with Alidoro.
• Alidoro can be found at the entrance to the Barren Swamps in Chapter 4.
• Alidoro has one weapon and amulet available for each Rare Ergo you own, so on your first playthrough, you must decide which one to purchase.
• If you decide you do not want either the weapon or the amulet available for any given Rare Ergo, then at that point you are safe to consume it and use the Ergo to level up instead.
• Those who lie to the hunter may find themselves unable to buy specific items due to their lies from before.
• Its worth keeping in mind that the weapons and amulets obtained from Alidoro are unique and cant be disassembled and mixed with others. They also require rarer Darkmoon materials to upgrade.

In summary, players should hold onto Rare Ergo until they find Alidoro in Chapter 4, and then trade them for special weapons and amulets. Its important to choose wisely, as the weapons and amulets are unique and cannot be disassembled or mixed with others.