Hint Toad

Blue Toad is one of the five members of the Toad Brigade, which act as Princess Peach's attendants and royal guards. He is the smartest member of the brigade and often helps Mario with the use of his knowledge.

Mario vs. Donkey Kong
Blue Toad made a reappearance in this game as one of the three Toad employees who worked in the Toy store creating Mini Mario toys. He was working peacefully until Donkey Kong arrived and had stolen the toys with brute force. Later on, Blue Toad along with the other 2 toads appear at the scene where Donkey Kong had dropped all the Mini Marios and had started laughing at him along with the others. However in his anger, Donkey Kong kidnaps the Toads and climbs up on the top of a building with the 3 in his arms. Fortunately, Mario once again manages to defeat the ape and saves Blue Toad and the other 2 Toads.

Super Mario Galaxy
In this game, Blue Toad appears as one of the five members in the Toad Brigade. He was said to have escaped with the 4 other toads and as well Luigi from the Mushroom Kingdom into Space however they were soon separated from Luigi. Eventually, Mario came along and saved the 5 Toads (including Blue Toad) in the Honeyhive Galaxy. Throughout the game, the Toad Brigade attempts to help Mario on his quest by travelling throughout the different galaxies in the search for Power Stars. In their last appearance in the game, the five Toads are revealed to have been promoted to being Royal Guards due to their work of helping Mario.

Of the Toad Brigade, Blue Toad was shown to be the smartest of the five Toads and had provided Mario with a lot of knowledgeable information about the galaxies. To show his intelligence, Blue Toad appears wearing glasses in this game and is called the "smart one".

Super Mario Galaxy 2
Blue Toad is once again part of the Toad Brigade in Super Mario Galaxy 2.

Personality
Ever since his debut appearance in the Mario series, Blue Toad is often portrayed as to being no different than other members of his species. Due to the fact that he is often shown alongside the companionship of other toads, Blue Toad was forced to be given small and generic roles in most of his appearances. His intelligence is further proven in Super Mario Galaxy where he provides many tips for Mario.

Trivia

 * In Super Mario Galaxy during some Purple Coin challenges, the Blue Toad will give the player advice about how to get some hard to reach coins.
 * Blue Toad shares many similar characteristics with the characters Toadbert, and Russ T. as they are all blue-spotted Toads, are intelligent, and wear glasses (though Blue Toad only demonstrates the last two traits in Super Mario Galaxy and Super Mario Galaxy 2).
 * It is not impossible that the Blue Toad from New Super Mario Bros. Wii is this specific Toad, as the two have strong similarities appearance-wise.
 * In Super Mario Galaxy 2, after giving the Banktoad 1000 Star Bits, he will wear a pair of glasses similar to Blue Toad's pair because he wants to look smart.