[Dormamu]

Without getting too deep, I think it's hard to draw comparisons from Emu to past riders.

Trope wise, there's always a morality theme for the central character. While some like Takeru's 'human potential is infinite....was terrible because his potential was to be a potato for days on end, others like Kouta were better because This power exists to protect those who can't fight.....admirable, and actually pretty good especially since Kouta was so comically challenged. Or
Haruto who really have a motivational other than to save Koyomi. Which he didnt.

Emu on the other hand seems to be motivated to not just save his patients, but to save them to the point that they can feel as happy as he does to be alive. He's trying to be Florence Nightingale.

Pretty appropriate for this episode too since apparently Nico is Taiga's morality pet. The episode setup was obvious. Both Taiga and Hiiro had their rough edges and by mid series that's usually enough time to turn it around. Overall though, this episode reached around on the Chris Matthews Creepy Meter to Level 99.

And I don't care if there's not enough character motivation for Emu to care about Poppy. SHE'S POPPY. She's no one's puppet!