Who says Voltron can’t take place a couple decades after Battle Network?
Zero.exe is Takashi Shirogane’s netnavi. He went with him and the Holts on the mission to Pluto and was subsequently captured by the Galra.
Zero was then modified by the Galra, just as Shiro was, but managed to escape with help from Marino.exe, a member of the Blades of Marmorra.
X.exe is an alien Navi, like Duo and Slur, created by the Alteans. He was put to sleep for a long time but woke up a year before the Paladins would arrive. The Arusians called him the Blue Guardian.
X is Allura’s NetNavi partner and they have known each other since the princess was a child. He was her tutor and friend, helping her cope with the loss of her mother. He was meant to be the next generation of Altean navi.
For the record, I liked the first couple of seasons of Voltron. I also liked how they referenced the original cartoon in the last season, but it could’ve been written a lot better.