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The Relic Fragment (Japanese: いせきのかけら Remain Fragment) is an object in Pokémon Mystery Dungeon: Explorers of Time and Explorers of Darkness and Pokémon Mystery Dungeon: Explorers of Sky. It is owned by the player's partner, who has had it for as long as they can remember.
Team Skull takes it twice over the course of the game. The first time is at the very start when the player and partner first meet Zubat and Koffing, the other being when Team Skull realizes the Relic Fragment needs to be used in order to get to Hidden Land. The first time, the player and partner go through Beach Cave, their first dungeon together and battle Zubat and Koffing to get it back. The next time, Team Skull gives it back when they are badly beaten up, right before Kabutops and Omastar are faced in Brine Cave.
The Relic Fragment only appears in front of good-hearted Pokémon. When taken to the bottom of Brine Cave, it interacts with a similar pattern on the wall, signaling Lapras to take the Pokémon to the Hidden Land. It must also be inserted into a small hole, in which it fits perfectly, to activate the Rainbow Stoneship, the mechanism for accessing Temporal Tower from the Hidden Land. In this way, it acts as a key to the Hidden Land, preventing all but those with the purest hearts from gaining access to Temporal Tower.
In the manga
The Relic Fragment in Pokémon Mystery Dungeon: Blazing Exploration Team
In the Pokémon Mystery Dungeon: Blazing Exploration Team manga
The Relic Fragment appeared in Pokémon Mystery Dungeon: Blazing Exploration Team while Totodile was tricked by a Koffing and Zubat of Team Skull into giving it to them. Totodile and Honō later retrieve it back from Team Skull after defeating them. It was later seen in Partners Reunited Once More, when Totodile explains to Grovyle how the Relic Fragment was what allowed Totodile and Honō to become an Exploration Team. In Aim for the Hidden Land!, when Totodile and Honō arrive at the entrance of Hidden Land via Brine Cave, the Relic Fragment begins to glow and a Lapras appears to grant them access to Hidden Land. The Relic Fragment was then placed into a pedestal to unlock the path to Temporal Tower. Totodile manages to have reacquired the Relic Fragment by The Final Battle for the Fate of the World!!, as Totodile reflects upon what happened since the future where darkness rules was prevented.