The most fascinating thing about Ultraman as a concept is the fact that this mysterious unknown being of light that came from a far away galaxy, a being so alien and unfamiliar to us, something beyond human comprehension... is actually very benevolent in nature.
The Ultras that did appear on Earth not come to rule or invade like any other sci-fi story involving aliens. They only came to help humanity face against whatever adversary is thrown at them because they sensed the strength to protect others in human hearts. Their selflessness and the potential to become better, kinder people is what resonated with these aliens, and that’s what why they reached out to Earth’s inhabitants.
Anyway I love the Ultra series, it's a fun sci-fi superhero series where giant aliens make friends with humanity and they wish for all of us to be good friends.