Which Mortal Kombat game introduced the villain Quan Chi?

Mortal Kombat Mythologies: Sub-Zero introduced the villain Quan Chi.

Released in 1997, Mortal Kombat Mythologies: Sub-Zero is a spin-off platform-action game centered on the original Sub-Zero, Bi-Han. Its story takes place before the events of the first Mortal Kombat and expands the mythology surrounding the realms and ancient artifacts.

Quan Chi appears in the game as a manipulative necromancer whose schemes involve the amulet of Shinnok. The title therefore established him before he became a major playable fighter and antagonist in later mainline entries.

A common mix-up is Mortal Kombat 4, where Quan Chi became especially prominent and was introduced as a playable character. Mortal Kombat 4 helped popularize him among players, but his first series appearance was in Mortal Kombat Mythologies: Sub-Zero.