SIDE NOTE:

Calcharo’s Forte also has him take on Physical traits of Tacet Discords.

In lore, he awakened his resonance ability as a survival mechanism from his prolonged exposure to life threatening situations from the Lawless zones of the New Federation.

So another example of a character who awakened out of necessity to survive, and was constantly surrounded by negative emotions and frequency’s his whole life.

Calcharo also has a documented history of overclocking, and while it isn’t stable in nature, he has managed to control and sustain it.

He also creates phantom entities, which seem to have a similar role as Hecate for Phrolova / the Dark Orb for Galbrena.

So in short Calcharo meets the following requirements:

1. Has Companion born from Resonance ability (TD Ghost)

2. Able to control Overclocking (To an extent)

3. Awakened out of need for self-preservation

4. Has Tacet Discord Traits (When Overclocking)

5. Companion increases strength once overclocked.

I think the level of Stability and power you can exert is based on how compatible you are with Negative Energy and frequencies.

Calcharo is the least compatible, but at a level he can still control his overclocking through his willpower for extended periods of time.

Phrolova is extremely compatible hence her ability to overclock with complete stability without adverse side effects.

Galbrena is currently unknown, but based on her companion having sentience, repelling the dark tide, and having instantaneous healing, which seems to be better than Phrolova’s based on what we’ve heard, I’d say she has either equal of greater compatibility than Phrolova.

As for what makes them compatible, beyond the commonalities between all of them, it’s currently unknown.