Mecha (メカ)
Reference to robot anime.
Gattai (合体)
Refers to the sequence where robots combine into one (i.e. Goddaner, Power Rangers, etc)
Visual Kei (ヴィジュアル系)
Type of Japanese Rock~
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Oniichan (お兄ちゃん)
An affectionate way of addressing an older brother.