Location from pokemon-kanto by
A man-made research island off Kanto's coast built by Giovanni for the Mewtwo experiments — destroyed and rebuilt by Mewtwo as a sanctuary for its clones.
New Island is the only location outside a research lab where Mewtwo has ever allowed trainers to visit — and the visit was a trap. Mewtwo invited the world's strongest trainers under the guise of a tournament, then attempted to prove clone superiority over 'inferior originals' by pitting its clones against their counterparts. The ensuing battle nearly killed Ash; Mew intervened; peace was reached; everyone's memory was erased. Mewtwo remains here with its clones in hidden exile.
A rocky artificial island with a dark castle-like research complex on its central peak. After Mewtwo's takeover, the complex is rebuilt in a gothic style with a main battle hall at its center. The island is shrouded in storm clouds Mewtwo maintains psychically.