Soundwave stopped talking.

It wasn't disastrous, as the Communications Chief continued conversing with his symbiotes and otherwise communicated quite a lot using whatever means necessary, be it audio samples, visuals or wireless comm. Anything, except his real voice.
Who knew it would make such a difference?

His voice was missed.

There had been other losses: bigger, more dramatic, with heavier impact... yet somehow this small loss symbolized them all.
The cycle that they had left their agonizing home planet in hot pursuit of their fleeing enemies was the cycle Soundwave had spoken his last words.

Coordinating their forced re-group, monitoring all the reports redirected to his private comm from the bridge console seemed not enough to keep the navy mech occupied. He used his free capacity to stare at Cybertron through one of Nemesis' window displays, watching the smoldering remnants of their home get smaller with their progress.

"We have killed it", - the spy said sensing the presence behind him, - "we have killed our home."
"The autobots..." - the other started only to get cut off by Soundwave's deep polyphonic voice:
"The Autobots _and us_. We all did".
Short silence settled between them as now both of the mechs looked at the tomb their planet was now and silently said their goodbyes.

"I vow". - Soundwave spoke up slowly, his rich voice low and reverberating, - "that Cybertron will rise again. From this moment, there is no goal for me but this. No rest, no doubt, no distraction."

A steel hand pressed upon the navy shoulder. Soundwave turned to face its owner and the only witness of his vow.
For a click their gazes locked then the spy's visor slid down and locked with fateful finality.

Nothing changed much since then.

Soundwave continued his relentless and devoted service, succeeding in cases when others had failed on sheer force of his will. He found a way both to keep the vow and to fulfill his communications duties.

The shut visor was his face now, audio scraplets were his voice. And even when he had to resort to automatically constructed speech, its voice was dull and most impersonal.
His presence had somehow turned into his absence and that was a constant reminder of what they all had lost.

Sometimes it haunted Megatron. Sometimes the weight became too much. Sometimes he questioned himself if there was anything left to fight for.

Such moments were rare, but when they occurred, the warlord would take a shift off and retire to his quarters so he could secretly, guiltily waiver in remorse and listen to a few old audio records he kept in his databank.

If one would stop at the Lord's door for long enough to attune ones hearing and listen he would pick up Soundwave's polyphonic voice singing ancient PIt's "song of slaves".

Sun's up - it's time to pay the energon price,
Pay for your passage into this paradise.
No matter if you're criminal or if you're legit -
Sooner or later we all get scrapped in the Pit.

The tribunes are chanting - they urge you get up
It never gets old and it's never enough,
Boost up your engines, return every hit -
But sooner or later we all get scrapped in the Pit.

Might have a life before, you might have a name,
No you're a noone, and we're all the same,
Carrying a tickling death inside your spark -
You pray for the moment, when lights turn to dark.

You came from the Well of sparks, all shiny and wet,
You didn't know this here is all you gonna get,
Hearing the siren makes your spark skip a beat -
Sooner or later, we all get scrapped in the Pit.

Deep in the night we sing the song of the slaves
One day - I vow! - we will brake all the chains,
One day we'll cash this debt, one day we'll rise,
We'll bring our fight up to their paradise!
There will be justice and freedom for all!
Stay online until the destiny calls
Stay online until the destiny calls
Stay online until the destiny calls
Stay online..
Stay online..

Megatron would squeeze his optics shut then and repeat his own vows, the ones that there were no witnesses to, because the only one who had access here was Soundwave and he never came.

"Treason will be punished by death. For all he's done, I'll extinguish the Traitor's Spark and all of those who follow him. Cybertron will be rebuilt and repopulated"

The Cause has to continue. Soundwave has to return.