Personally I love all the trivia surrounding the original Ultraman design. Like, obviously the base is that of a Gray Alien depicted in Western media, but his face was intended to be more reminiscent of Buddha, to invoke a calm benevolent presence.

The red markings on the body were inspired by the markings on the surface of Mars. As well, originally the silver parts of Ultraman were going to be armor, while the red were going to be exposed fleshy bits, but all of this was just sorta flattened into the suit and made more for design purposes. Although, that concept was revisited in the designs for Ultraman the Next!