Agatha and Bertha are sisters that were both born in Sinnoh, but Agatha travelled to Kanto as a young trainer, where she met Oak. Agatha got fixated on competing with him because he was constantly defeating her, so she moved to Kanto, where she eventually became an E4 member while Oak retired from battling. Meanwhile, Bertha, who was a lot more calm and passive than Agatha, remained in Sinnoh, where she also joined the E4 there.