Dr. Toadley -or Doctor Kokino as he’s known in Japan- works at Toadley Clinic in Toad Town. His first appearance was in the 2009 Nintendo DS game Mario & Luigi: Bowser’s Inside Story where the game’s chief protagonists Mario and Luigi need his help so pay him a visit. Dr. Toadley tells them that he needs three Star Cures so he can make a Miracle Cure to cure the Blorbs (a mysterious disease that affects Toads causing them to swell up and become mostly immobile).
As well as appearing in the recent Nintendo 3DS remake Mario & Luigi: Bowser’s Inside Story + Bowser Jr.’s Journey, Dr. Toadley also returns in the 2017 3DS remake of the original Mario & Luigi: Superstar Saga game for the Game Boy Advance with Mario & Luigi: Superstar Saga + Bowser’s Minions. Here, Dr. Toadley replaces Psycho Kamek from the GBA original and hypnotises Luigi so he can complete the mission on his own and find a cure, after Mario contracts Bean Fever.
Toadley’s appearance is mostly concealed under his mystical outfit where he is usually seen with both his crystal ball and his pet bird Birdley, who helps both Mario and Luigi in their adventures. With his crystal ball, Dr. Toadley is said to know everything there is to know about the Mushroom Kingdom. Although only appearing in a three games thus far (including both remakes), it is to be expected that Dr. Toadley will return for the inevitable Mario & Luigi entry on Nintendo Switch.