Which artist designed Tails for Sonic the Hedgehog 2?

Yasushi Yamaguchi designed Tails for Sonic the Hedgehog 2.

Yamaguchi was a Sonic Team artist and zone designer who created the fox character during development of Sonic the Hedgehog 2, released in 1992. His design won an internal contest for a new companion who could serve as Sonic's sidekick and as a second playable character, allowing two siblings to play together.

The character's original name was Miles Prower, a pun on “miles per hour.” Sega of America preferred the marketable name Tails, and the eventual compromise made Miles Prower the character's full name and Tails his nickname. Yamaguchi also gave him two tails, drawing inspiration from Myau, a cat-like character in Phantasy Star.

Players sometimes confuse Tails's designer with other major Sonic artists. Naoto Ohshima co-created Sonic, while Kazuyuki Hoshino and Yuji Uekawa are associated with later Sonic art and character work. Yamaguchi's role here specifically concerns Tails's original design and his artistic work on Sonic the Hedgehog 2.