Birth! Z Tretta!! (Japanese: 誕生！Zトレッタ！！) is the first set in the Pokémon Tretta Ultimate Z series, and the nineteenth overall. It features 48 Tretta.
Birth! Z Tretta!! is the first set of the Pokémon Tretta Ultimate Z series, a continuation of the Pokémon Tretta Ultimate series with particular focus on the Legendary Order Pokémon Zygarde in its constituent forms. This series introduces Z Tretta, which have additional capabilities such as the ability to summon Pokémon to aid a player in Battle Mode, similar to the role of Advent in Pokémon Battrio, or the ability to change their form. Z Tretta are identified with a icon. Birth! Z Tretta!! features Zygarde in its 50% Forme as an Ultimate-class and a Hyper-class Tretta with the Z Tretta ability, which allows Zygarde to transform into its Complete Forme when its HP drops below half. The Legendary beastsRaikou, Entei, and Suicune are also featured as Master-class Tretta with the Z Tretta ability. Each member of the trio have a chance to summon either of the other two members if used in Battle Mode, but if all three are used together, the Legendary Rainbow Pokémon Ho-Oh will always be summoned. Additional Pokémon summoned via the Z Tretta ability will attack after the conclusion of Round 3 in Battle Mode. If the player has any Extra Attackers, any Z Tretta-summoned Pokémon will attack afterwards.
Location icons in Search Mode may feature sparkles if a high-class Pokémon will be encountered there, a new feature from this set. Locations also have a winter theme, with Foot replacing Ruins from the last set.
Birth! Z Tretta!! also introduces Tretta with one-hit knockout moves, identified by red text on a move segment. Much like their core series counterparts, their accuracy is considerably lower compared to that of regular attacks, but a successful hit will fill the Catch Gauge of an opposing Pokémon completely.
Challenge Battle includes five new line-ups for players to compete against, including two new Tretta Leaguer types, Naughty Leaguer and Tretta Doctor. Tretta Idol Hitomi and Top Leaguer Tatsuya return, but this time as the 4-star and 5-star challengers. Players with Tretta Reports could also add the Aura Pokémon Lucario and Legendary Alpha Pokémon Arceus to their Extra Attacker roster through repeated play.