Bankai Name Generator

In Bleach, a Bankai is the final release of a Soul Reaper's Zanpakutō, and its name almost always grows out of the Shikai name rather than replacing it. Byakuya's Senbonzakura becomes Senbonzakura Kageyoshi (Vibrant Display of a Thousand Cherry Blossoms), Hitsugaya's Hyōrinmaru becomes Daiguren Hyōrinmaru (Grand Crimson Lotus Ice Ring), and Ichigo's Zangetsu becomes Tensa Zangetsu (Heaven Chain Slaying Moon). The added words describe how the power has intensified: a bigger scale, a new color, a divine or Buddhist title.

Tite Kubo pulls his names from classical Japanese, Buddhist iconography, and poetic nature imagery. Some Bankai are complete phrases (Zanka no Tachi, Longsword of the Remnant Flame; Kamishini no Yari, God-Killing Spear), some borrow deities and guardians (Kokujō Tengen Myō'ō names a Vidyaraja wisdom king), and a few use a colon to add a subtitle, as in Katen Kyōkotsu: Karamatsu Shinjū. Almost every name has three to six syllable groups, heavy on long ō and ū vowels, which gives it that weighty, ceremonial sound.

The names here include the canon Bankai for reference and a large set of original names built the same way: evolved Shikai forms, X no Y constructions, and full titles drawing on the four guardian beasts, Shinto deities, and Buddhist figures. Pick one that fits your OC's element and personality, then decide what the release actually does.