Just going to leave this here:

A "fancy piece of Ladeca" is the most likely thing based off our current knowledge so you might have already answered your own question, lol. Another possibility is just that some character designers just wanted to put a glowy blue thingy somewhere on the character and never actually considered what it would really be. Unless one of the keyword discussions actually mentions what it is though, I don't think we'll ever know for sure.

Yeah, I suppose so.

I was just really hoping there was a reason behind it, some interesting story added that's all! c: