Atlus has introduced new treasure personas in Persona 5. Capturing them will give the players the opportunity to craft more powerful creations, especially if they have the Queen's Necklace.
Usually treasure demons are found in the dungeons. Specifically, the Queen's necklace is located at the third main palace called Kaneshiro's Bank. Once players reached the place, they should head to Banker Passageway area. If they are having a hard time, they can always use the Treasure Trap.
According to Mic, they need to go up via stairs to reach to the top. However, there is a patrol dog there so they must be careful while ascending. They should check every room along the hallway to make sure the Queen's Necklace is there.
In order to do that, they must hold down L1 and wait if the object in their hands will turn into a diamond and run away. Immediately, they must hit it and the Queen's Necklace will ask you to fight it. They need to know that its gunfre is weak, so players can shoot it.
They need to take advantage of the Queen's Necklace's weakness in order for it to surrender. Once the demon gave up, they can ask it if it can join their team in Persona 5. Right away, the demon will agree to their negotiation.
Once they have the Queen's Necklace, they will be able to know its strengths, namely the Physical, Ice, Fire, Psy and Nuclear, as per Gear Nuke. The demon maybe weak in gunfire but it can be overlooked especially when they use it to fuse with other personas.
However, they must never forget that the treasure demons are not allowed to be used in fighting in Persona 5. It means they can only use them as an ingredient instead of letting it fight for any opponents they will soon face.
