Kapalı Kale is the best-known organised supporter group associated with Kayserispor.
Kayserispor’s official website identifies the group as an independent supporter organisation founded in 2008, known for following the team both at home and away.
Kapalı Kale remained highly active in 2026. The group issued public statements on club affairs, organised season-ticket mobilisation and prepared new banners ahead of the 2026/27 campaign.