Theory:Doctor Who television discontinuity and plot holes/The Halloween Apocalypse

The Lupari
"The Lupari are species-bonded with humanity, meaning each human had a Lupar to protect them".

So, there are multiple reasons as to how this premise makes absolutely no sense, but I'll start with the biggest and most obvious: how is this the first time we're hearing of this? Why has literally no other human in the history of the DWU had a Lupari show up to intervene in their lives?