Counterpart to Halo, in a very literal manner. Both Vectra and Halo follow a magical girl formula of sorts, their artefacts allowing them to transform into their superform.

The twist is that when one transforms, the other is imminently forced to as well, and both can only power-down when both are relaxed. Thus, whenever Halo goes to fight crime, she generally finds Vectra being a nuisance, and when Vectra tries a score, Halo almost inevitably intervenes.

It'd take a few encounters for them to realize their connection, and from that frustration with each other begin trying to negotiate times and warnings to avoid rumbling their private personal lives.

Essentially, eventually, Halo and Vectra get a text chat to schedule super stuff and give fair warnings.