Gladis is a character found in Tears of the Kingdom.
Tears of the Kingdom
Gladis can be found outside the entrance to the North Hyrule Plain Cave. They came to the cave seeking a Bubbulfrog, at the request of two people from Woodland Stable who will trade treasure for a Bubbul Gem. Gladis is too scared to go inside the cave, so they are standing outside.
Once Link possess a Bubbl Gem, Gladis advises seeking out the two characters at the Woodland Stable who wanted it.