Gianism Best Ofs consists of four best of albums released by Nightmare.
The tracks on Gianism ~omae no mono wa ore no mono (ジャイアニズム ～お前の物は俺の物～) and Gianism ~Ore no mono wa ore no mono (ジャイアニズム〜俺の物は俺の物〜) are songs from the band's 'indies' era; they performed these songs during their earlier tours.
These two albums were also released as a limited edition double album.
The album Gianism ~Nightmare no Kuse ni Namaikidazo~, consists of their best of songs after they went major.
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