Veldora Tempest

ヴェルドラ=テンペスト, Verudora Tenpesuto
Storm Dragon Veldora Tempest Boufuu Ryuu Verudora Tenpesuto is the youngest of the four strongest dragons True Dragons. He is connected with Rimuru by an agreement and was known to rampage here and there. He was the one to name Rimuru and Rimuru gave him his last name since they share the same last name Rimuru could technically be classified as Veldoras adoptive brother.