Glaciate! Kyurem Assault (Tretta)

Following on from the theme of the Pokémon Tretta Ultimate series established in the previous set, Glaciate! Kyurem Assault features the Legendary Boundary Pokémon Kyurem as the eponymous Ultimate-class Tretta. It can use its signature move Glaciate and is the first Pokémon in Pokémon Tretta to have a base stat with a value exceeding 300. The Tower duo Lugia and Ho-Oh also make their Pokémon Tretta debut as Legend-class Tretta.

Among its selection of Pokémon, Glaciate! Kyurem Assault includes eight capable of Mega Evolution. These comprise Sceptile, Blaziken, Swampert, Banette, Steelix, Mawile, Gengar, and Slowbro. Legendary Pokémon Zekrom and Reshiram complete the Tao trio, appearing as both Master-class and Super-class Tretta. A Secret Tretta is also included in this set after a one set absence, featuring a Shiny Magikarp on a metallic yellow-colored Tretta. All regular Tretta in this set are colored ice blue.

Search Mode retains all locations from the previous set with the exception of Beach, absent for the first time since Search with Meowth! That Trio!!. The number of available locations was also reduced from 6 to 5, reverting to the original number last seen in Experience Mega Evolution!.

After obtaining the previous Pokémon via Challenge Battle, Glaciate! Kyurem Assault offers players with Tretta Reports the chance to acquire the Legendary Genetic Pokémon Mewtwo as an Extra Attacker through repeated play. The Mischief Pokémon Hoopa could also be encountered for the first time in Challenge Battle from this set.

In addition to its debut in Challenge Battle, a new game mechanic involving Hoopa was introduced from this set. The Ultimate Class Appearance~! System (Japanese: アルティメットクラスをおでまし～！システム) may activate if the player is not using any Ultimate-class Tretta. If activated, Hoopa will appear at the end of Round 3 in Battle Mode and summon a Pokémon that has appeared an Ultimate-class Tretta from one of its rings. That Pokémon will randomly attack either the player's party or the opposing party, potentially changing the outcome of Battle Mode. This mechanic was discontinued with the release of the Hyperspace Fury! Hoopa Transformation set.