After the abduction of his brother Kotaro by the Machine Empire, Teppei Takamiya joins forces with X, one of several highly-advanced, artificially intelligent machines known as B'ts (pronounced 'beat'), to rescue him. Volume Subtitles: 1: **X Revival!** (エックス復活!, Ekkusu Fukkatsu!) 2: **Far Way to the Area** (エリアへの遠い道, Eria e no Tōi Michi) 3: **Heart Color** (心の色, Kokoro no Iro) 4: **Five Color Phosphorescence** (五色の燐光, Goshiki no Rinkō) 5: **The Seven Greatest Demons** (最凶の七魔将, Sai Kyō no Nana Ma Shō) 6: **Fragment of the Sun** (太陽のかけら, Taiyōnokakera) 7: **Song of an Angel** (天使の詩, Tenshi no Uta - ALT ENG. Angel's Poem) 8: **Forest of Oblivion** (忘却の森, Bōkyaku no Mori) 9: **Nightmare Battlefield** (悪夢の戦場, Akumu no Senjō) 10: **Blood Battle! Kamui Island** (血戦！神居島, Kessen! Kamui-Jima) 11: **Area Collapse** (エリア崩壊, Eria Hōkai) 12: **Shellfish** (貝えぬもの, Kai Enu Mono) 13: **Deathmatch of Intelligence** (智力の死闘, Chiryoku no Shitō) 14: **Faithfulness** (信しる心, Shin Shiru Kokoro) 15: **Hurry Light!** (光よ急げ!, Hikari yo Isoge!) 16: **Eternal Path** (永遠の軌跡, Eien no kiseki) Note: Volume count based on the bunkoban. Link: [AnimeNewsNetwork](https://www.animenewsnetwork.com/encyclopedia/anime.php?id=527) (anime)