Birth! Z Tretta!! (Tretta)

'''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.

Information
''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 Order Pokémon  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 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 beasts, , and 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 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.

The numbering system for the series prefixes the set number with "Z", which reverts to 1 with this set. Another cross promotion with the Pokémon anime also begins with this set, with Shiny versions of two members of the aura trio, and, featured as Legend-class Tretta following the availability of their core series counterparts prior to the set's release. Another based on the one belonging to Ash Ketchum is featured as a Master-class Tretta, as are a Shiny  and  capable of Mega Evolution. These Pokémon are based on those belonging to Steven Stone and Alain from the Mega Evolution specials respectively. Other Pokémon capable of Mega Evolution in this set include and new addition.

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 and Legendary Alpha Pokémon  to their Extra Attacker roster through repeated play.

Challenge Battle Tretta Leaguers
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