Headcanon time: Nada said that his reason for approaching the team in episode 26 was to see what kind of person Red was, but part of me likes to believe that’s not true, at least, that’s not the only reason. If he just wanted to check and see what kind of person made it as RyusoulRed, he could’ve just observed from a distance. Or he could’ve seen it from behind the mask of Gaisoulg.
Nada knew his time was limited, that sooner or later the armor would take over completely and he would be lost forever, and I’d like to think that that’s why he chose to approach them, because before he would be gone, he wanted the kids to know him as himself, as the kind person he used to be (and still is underneath the armor). He wanted someone to have fond memories of him and not just remember Gaisoulg.