Sync stone

A sync stone, as seen when a sync pair's moves level up

A sync stone (Japanese: バディストーン buddy stone) is a special type of stone in Pokémon Masters EX. These stones are powered by the bond between a Trainer and their Pokémon, and they allow sync pairs to use sync moves, Z-Moves, and certain transformations.

The interaction between sync stones and Pokémon is the main subject of Professor Bellis's research.

In the games

Sync stones are small, rainbow-colored stones that are found only in the seabed around Pasio. After being mined, sync stones are embedded into Poryphones and given to all sync pairs who arrive on Pasio. This gives all Trainers on Pasio access to sync moves, though whether a Trainer and Pokémon actually have the ability to use sync moves is determined by their sync strength. Sync strength (Japanese: バディーズちから buddy's strength) is the power that comes from the bond between a Trainer and Pokémon, and it is amplified by sync stones. Tapping into that strength allows sync pairs to use sync moves. A sync stone's ability to amplify sync strength appears to be affected by the Poké Ball in which the Pokémon has been caught, as Together in an Unknown Land demonstrates that Akari struggles to use sync moves with her Pikachu because it is held in a Hisuian Poké Ball.

As the bond between the Trainer and Pokémon grows, so does their sync strength. However, the bond does not have to be one of friendship in order to power sync moves. For example, it is revealed in Team Rocket Returns that Giovanni and Mewtwo's sync strength is powered by their shared proclivity for malice. Conversely, if a Trainer and Pokémon do not have a bond, or the bond is one-sided, the pair cannot use sync moves. For example, at the beginning of the PML Arc, Lear cannot use sync moves because he thinks bonds are stupid and useless, and he only relies on himself. However, after he realizes that he needs to care about his subjects as a king and accepts Hoopa's friendship in Shining Bonds, he becomes able to use sync moves with Hoopa.

Whenever a Trainer and Pokémon accept each other as sync partners, the Trainer's sync stone glows. For example, Lear's sync stone glows when he accepts Hoopa's friendship, and in Protecting the Island, Acerola and Lana's sync stones glow when they earn the respect of Tapu Bulu and Tapu Fini, respectively. A Trainer's sync stone also shines before they use a sync move with their partner.

The mysterious stones found across Pasio in the Mysterious Stones Chapter have some similarities to sync stones. This led Professor Bellis to officially name them sync stones ultimate.

Sync stone energy

Sync stones hold a a great deal of energy within them, which is similar to the energy involved in Mega Evolution, Z-Moves, and Dynamax. Some Pokémon can Mega Evolve when using their sync move, without the use of a Key Stone or a Mega Stone. Some Trainers, primarily those from Alola, use a Z-Move as their sync move without needing a Z-Ring. A sync stone can also be used to Dynamax or Gigantamax a Pokémon without the use of a Dynamax Band. In addition, Eternatus can use sync stone energy as an energy source, but it has to use sync moves in order to absorb the energy properly. In Howling Shield of Eternity, Leon forms a sync pair with the Eternatus on Pasio specifically so he can help it absorb sync stone energy. Sync stone energy appears to also be similar to the energy contained in the Prison Bottle, as Paulo is able to use his sync stone to change Lear's Hoopa into its Unbound form during The Path Forward.

Sync stone energy can affect not only the Pokémon, but the Trainer too. In Delta of Land, Sea, and Sky, Petrel and Proton each claim to know a way to use their sync stone to control Groudon and Kyogre, respectively, who are going on rampages. They share their advice with Courtney and Matt, respectively. However, when the admins try to do this, their sync stones end up making Groudon and Kyogre's rampages affect them. While no explanation is directly given for why this occurs, it may be related to a conversation that takes place in Hearts Connected by Fashion. Elesa says that sync moves only happen when a Trainer's heart and mind are in complete sync with their Pokémon's, and Valerie says that unity makes her feel like she has become her Pokémon. Thus, when Matt and Courtney unite their minds with Kyogre and Groudon by using their sync stone, the rampage affecting Kyogre and Groudon's minds ends up affecting Matt and Courtney's minds as well.

In A Millennium into the Future, Rose becomes very interested in sync stone energy for its potential to power things outside of battle. He wants to focus sync stone research entirely on its potential as an energy source, and when Professor Bellis and Lear refuse, he acquires the professor's sync stone data and starts independently developing technologies that utilize sync stones as an energy source. He forms a partnership with Clemont, Volkner, and Sophocles to make inventions that use sync stone energy; however, they break off the partnership after realizing that Rose thinks their ideals are unnecessary for the future he envisions. After Leon, Victor, and Lear demonstrate the power of their sync stones in battle, Rose finally admits that a purely scientific approach won't work for drawing out the full power of sync stones, and he agrees to work with Lear and Professor Bellis to research sync stones and their energy.