Series

In general, the fact that everyone from Ultraman Cosmos, Musashi, and Team EYES are more focused on protecting monsters rather than destroying them. It's to the point that this series has the lowest bodycount in the Ultra Series.
Cosmos and Musashi's relationship in general. Unlike other Ultras and Hosts where they have no interactions besides switching bodies or transforming, Cosmos and Musashi act as close friends, or at least share a mentor-student relationship. They both care for each other and tried their best to save each other a couple of times.

Episode 1: Reunion with Light

Musashi calming down Chaos Lidorias by using the special crystal that he used to play with her, it proves enough to bring her back to her senses, overcome Chaos' corruption and go back to playfully playing alongside Musashi. Too bad, the JAFD ended ruining it.

This episode deals with a guest character of the week, Shunji Horimura, who's a 14 year old genius and loner that's separated from his old friends in different schools while dealing with the prospect of making new friends. His boring life changed after an encounter with Sol, an alien teenager who followed his late father in studying Delgoran until the monster became corrupted by Chaos Header. They eventually became fast friends due to their common ground but as Delgoran was defeated, Shunji knew that he and his alien friend are going to part. After this, Shunji made his first step by joining the rocket club and eventually making new friends in his mid school life.
- Apart from that, when Sol was offered a contact with Musashi, he only wishes for Delgoran to be cured than to be killed. The boy regarded said monster as his Only Friend during his long time space travel and knows full well that avenging his late father wouldn't get him anywhere.

The fact that Tomano only summoned Gruanfan as means of reliving his memories, even in spite of them not being all that outstanding next to any other live. He clarifies that it might have been an ordinary life unnoticed by everyone else, but he lived it as best as he could, which is all that matters to him. He is happy enough to relive them, that when his time to disappear per the rules of those that summon Gruanfan, he takes it calmly, happy to have relived his memories of life one last time.

The Series Finale. Instead of an epic final battle against Chaos Header ending with the latter's destruction, Cosmos and Musashi do the impossible and succesfully redeem the seemingly pure evil being, with the help of some of their monster friends (Lidorias, Mogrudon and Bolgils) who assist them by using their voices to reach out to Header's inner goodness and allow Cosmos to use the Full Moon Rect to purge all the evil from Header and turn it into a being of good, who peacefully leaves once pacified alongside Cosmos as company, no longer desiring to cause harm to anyone.
- Cosmos's goodbye to Musashi. The Ultra gave a So Proud of You speech to his host for helping him do the unthinkable. Musashi tearfully says that he still wants to fly with Cosmos just like when he was young, but Cosmos told him he could fly on his own. Finally, after ensuring Musashi that he can keep earth safe on his own, Cosmos flies away with Musashi happily waving goodbye to his Ultra.