Just what exactly happened to Kyle's saber between DFII, MoTS and Jedi Outcast. First it was green, then orange and now blue respectively, is there a mentioning of this in a book I haven't read yet or...
The change between DFII and MoTS is explained, Kyle's (green) lightsaber was destroyed and took Yun's (orange) lightsaber. The change of orange to blue between MoTS and Jedi Outcast was that Kyle constructed his own saber between the two games, before he severed his connection to the force.
Actually, Yun's was yellow. So, he changed sabres between Jedi Knight and Mysteries as well.
He probably just switched crystals between games, loss of the green sabre notwithstanding.