Katrese's Bayleef is a Pokemon obtained by Katrese. Katrese caught her as an Chikorita.
Katrese was traveling with Gabe, Erika, Crystal, and Cilan when she saw a Chikorita sleeping which was very usuaal because Chikorita are only found in Johto. Determined to catch the Chikorita, Katrese sent out Braixen to fight it. But it is revealed that this Chikorita was abandoned by its trainer and was scared of fighting other Pokemon. Katrese asked the Chikorita if it wanted to join them. Chikorita agreed and joined its new trainer. Chikorita was confirmed female when Katrese's Braixen fell in love with it. Chikorita and Delphox were captured by Team Rocket, but were rescued by Katrese. During a battle with Ramos, Chikorita evolved into a Bayleef and Katrese was proud, but Bayleef was captured by Team Rocket who wanted to take Bayleef to the boss as a gift. Katrese rescued her Bayleef and sent Team Rocket blasting off. During a battle with Erika, Bayleef evolved into Meganium.
Meganium as a Chikorita was very affectionate to her trainer even though she was scared at first having been abandoned. But she cares about her trainer very much and loves her. When she evolved, Bayleef showed more care for her trainer especially when her trainer protects her from Team Rocket. When she evolved into Meganium, she loved her trainer even more.