Gosh Liu and Naidan make a good pair, they clearly care a hell of a lot for each other. Even near death, Naidan's last words were a word of warning, I assume, to protect Liu.
I'm very curious what Naidan's (and Worm's) goal is with Ryuki. Naidan knew he would get killed this fight, based on his words to Liu in ch 84. We also know now that Ryuki is the Omega and the Last Child, so he's definitely the last something (maybe Tiger's Vessel? Or something related to Gaoh Mukaku), and now he's the "connector" to the "future", where he's going to lead The Worm. Clearly, this is related to Gaoh Mukaku and Ryuki's past with Worms, but considering their hatred for Worms, something HUGE must happen for Ryuki to even think about leading The Worm, and part of it is probably to get Ryuki to start doubting his grandfather's words. Which is why, I think, Naidan chose to die just like that. I look forward to this development.