The Soul Dew (Japanese: こころのしずくSoul Dew) is a type of held item introduced in Generation III. From Generation III to VI, it boosts the Special Attack and Special Defense of Latios and Latias; in Generation VII, it boosts the power of their Psychic- and Dragon-type moves instead.
This section is incomplete. Please feel free to edit this section to add missing information and complete it. Reason: Does it check the Pokémon's species before or after using Transform (in each generation)?
Latias sight-sharing with Latios while in Soul Dew form after its sacrifice
The Soul Dew appeared in Pokémon Heroes: Latios & Latias, in which it is used to guard Johto's Alto Mare. It was given to an old couple in Alto Mare long ago after Latios and Latias saved the city. The duo of Annie and Oakley were looking for Soul Dew as well as the two Legendary guardians of the city, Latios and Latias. If the Soul Dew is attached to the Defense Mechanism of Alto Mare (DMA), anyone using the device can drown the city in water, block all exits in the city and awaken the Fossil Pokémon, Kabutops and Aerodactyl. It is implied that this Soul Dew contains the soul of a deceased Latios.
Soul Dew was introduced as a Trainer card in the Pokémon Trading Card Game during the Japanese e-Card Era. Released in the Theater Limited VS Pack half deck, it features an illustration by Hiromichi Sugiyama. This Trainer card allows the player to search their deck for a Pokémon with Alto Mare in its name and add it to their Bench; they may also move an Energy card from another of their Pokémon to the new Pokémon before shuffling their deck.