Toad

Toad is Princess Peach's attendant, a member of the Mushroom Retainers and a longtime protector of the Mushroom Kingdom.

Super Mario Bros.
In Super Mario Bros., Toad and the other Mushroom Retainers were kidnapped by Bowser during his first invasion of the Mushroom Kingdom. They were held hostage in separate castles, guarded by Fake Bowsers. After being saved by Mario and Luigi, they reminded the duo that Princess Peach wasn't at their castle.