Connie, one of the main characters in Mario & Luigi: Brothership, is generally positive and proactive throughout the game, yet she often mentions her sadness regarding her missing mentor, Ms. Cozette. Cozette apparently vanished at the same time the original Uni-Tree was destroyed and the world of Concordia was broken apart. In flashbacks, players can see glimpses of this kind teacher who inspired and guided Connie in her life, and it leaves a bit of an ominous tone for what could have happened in this story-driven RPG where nobody really seems to die.

https://screenrant.com/mario-luigi-brothership-connie-mentor-cozette-spoilers/