Species bond
From Tardis Wiki, the free Doctor Who reference
A species bond existed between each Lupar and their designated human. The bond's purpose was to save them, and the Earth against an event called the Flux. Karvanista was bonded to Dan Lewis. (TV: The Halloween Apocalypse) However, humans were never informed about this due to being a Level 5 planet, so the plan equated to an alien abduction; which Karvanista made worse by blowing up Dan's home on the way out.
While they were species bonding, the Sontarans got behind the Battalion wall in the milisecond before it was made and launched temporal attacks across time. (TV: War of the Sontarans)
