Relationship with Cadance
In Cadance Knows Best, when Cadance begins to babysit, Isamu begins to play with her shoes and then, his best big cousin. Then, Isamu kissed Cadance by her hoof.
Relationship with Luna
Prince Isamu thinks that his mother, Luna is someone he would always loved. So, He'd never stopped loving her ever.
Relationship with Maid Marian
In Isamu and Maid Marian, Marian was granted permission to babysit Isamu while Robin Hood is on the Archery Tournament and that is when Isamu begins to like Marian.
In Marian the Great Babysitter, Isamu begins to like Maid Marian when she was to babysit again.