Theory about Dark Wielders - OS Spoiler

Ok so I'm on a binge right now where for about the past month all I've been doing is listening/reading the books over and over again.

It's kind of interesting the things that jump at you at different times.

Some of the Venin seem to have multiple signet-like powers.
Take Theophenie for an example.
She claims to be a stormwielder, but at the same time she can "blink" as in transport herself to places very quickly. Some others can also do this.

So I was thinking, since Venin are channeling from the earth, and not a dragon, maybe they are able to teach each other their signets...

This also plays into something else I've noticed, Theophenie tells Violet there isn't a lightning wielding Venin, she tells her Violet is the exception to the balance.

If venin are able to learn and teach each other signets, that would mean a lightning wielder never turned Venin before.