ケルディオ

Keldeo is the Colt Pokémon, a Water/Fighting-type Mythical Pokémon introduced in Generation V (Pokémon Black and White). It is the youngest member of the Swords of Justice alongside Cobalion, Terrakion, and Virizion, who raised and trained it like a student. Spirited and resolute, Keldeo can adopt its Resolute Form by mastering the move Secret Sword, with its true power said to awaken only after enduring harsh battles and fully developing the horn on its forehead.

The Japanese name ケルディオ (Keru디o, romanized Kerudio) and the identical English 'Keldeo' are thought to derive from words evoking horse-like nobility and water; common interpretations link it to the Latin 'celer' (swift) or to 'colt'/'cavalry' imagery combined with a sound suggestive of 'aqua' or 'deo' (a god-like, divine element). As the kana ケル-ディ-オ simply transliterate the coined name rather than spelling out kanji, the meaning is intentionally evocative rather than literal, reflecting a swift, water-natured young steed. The English name is a direct romanization of the Japanese, kept identical worldwide.