Ivy is my choice for I. Like many, I expected her to be the Camilla of Engage based on her first cutscene and the opening. What we got instead is an endearing dork that worships the Divine Dragon to rebell against her homeland. Her relationships with her retainers and Hortensia also provide some wholesome moments. Her battle convo with her father is bittersweet, but nice all the same. While part of me wishes she had some resentment for the Brodian princes, her wishing to repair relations alongside Diamant shows her desire to move towards a better future.
Honorable mention goes to Inigo and Innes. The former has his flirting being a way to mask his shyness and a way to inspire others in a otherwise hopeless situation, while the latter is hillarious in his petty one-sided rivalry with Ephriam.