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The Robin suit is the protective suit and combat armor which was first worn by Dick Grayson. He fought alongside Batman in Gotham City. At some point, he gave up the mantle as Robin and became the Nightwing, giving the Robinsuit to Jason Todd.
The second user, Jason Todd, took up the mantle as Robin who, similarly to Dick Grayson, fought alongside Batman in Gotham City until his death at the hands of the Joker and Harley Quinn, which left the Robin suit damaged and graffitied with the sentence "HAHAHA, JOKE'S ON YOU, BATMAN" (in yellow spray-paint). Following this, the retired suit would be kept by Bruce Wayne who left it on display inside a glass case in the Batcave to serve as a reminder and fuel his vigilante activities.