Long ago, long before Orion Pas was an adult, there was a laboratory way out in the middle of nowhere. It was mechs and femmes that had the theory of making a Cybertronian with the ability to be a spark eater without the danger of losing their processor when they changed over to follow their programming. Spark eater were dark creatures that feasted on sparks of the living, very rarely would they attack a city. A crazed mech, with no name except Doctor, decided to harness the power of theses creatures that strike fear into even the spark of the great Prime. So after mastering a way to capture the Spark Eaters.
They tried to build them bodies to use. So far all failed.
Then there was one.
It was a small femme, her name was Echo, the Spark Eater placed inside of her processor and programmed didn't try to rip out her spark and eat it. She played around just like a normal sparkling. No threat.
Soon the experiments began to work. They created one to be both a femme and a mech, to be a Spark Eater Secret Agent or whatever. Her name was Angel.

"Hi Echo!" Angel squealed happily as she hugged her crush close "Let's go shower!" Echo didn't really speak all that much, she was usually silent. Angel grabbed Echo's servo and dragged her to the showers. The one place in the entire laboratory that didn't have cameras. Angel helped Echo take off her armor before taking off her own, then pinned the smaller and weaker femme to the wall, kissing her roughly, leaving bruises on her lips, neck, and chassis. Echo squeaked and tried to call out for help, but her own fear silenced her. Angel pulled Echo's body close to hers, rubbing against her. Touching her body all over, scratching her back as she gripped it with pleasure.
The door was always locked, and no one could hear you inside the wash racks.
Angel threw the smaller femme to the floor and changed to her mech form getting on top of her, kissing her deeply "I love you~" Echo squeaked and tried to shove Angel off "Please, not again, I'll be good, I promise!!" But Echo wasn't strong enough. Angel kept kissing the smaller femme and moving down lower. Eating her out. Echo couldn't help but moan and groan. She shook, holding back the tears the best she could. Her whole body shook as she gripped the floor. She cried. Angel finished when Echo came then crawled up to her and kissed her tears away before slamming inside of her. Echo screamed out! "Yes, love, scream as loud as you want, they can't hear you~" angel purred as she began a very rough pace, ripping more and more of Echo on the inside. It hurt so bad! Angel kept going after they both came again. Until a knock on the door was a ten minute warning. After getting out of Echo and changing back to a femme, she helped the smaller femme wash up, dry off, and get her armor back on.

This treatment went on for years.
Echo was mistreated and raped by Angel every single day.
The only thing stopping Echo from asking for help was the fact that she was very shy and antisocial.
She felt so empty and alone, broken.
Finally when someone got tired of the experiments they attacked the laboratory Cybertronians. Everyone broke free and took off. Echo killed the Doctor, the Spark Eater inside of her was very angry and slaughtered the Doctor with that very rage that was built up from Angel, who followed Echo as she escaped. They ran everywhere. Living in a few places only a cycle or two. Angel continued to rape Echo thinking the femme was in love with her. They came to the City of Primes where Angel left Echo to go search for energon. It was two cycles and Angel hadn't returned. Echo clicked and waited for someone to reply. Suddenly someone did! In clicks as well! She saw someone and scooted backwards, hiding. The new being soft began talking to her, telling her that he wouldn't hurt her. Then when he went to leave she leaped out and hugged him "Please don't leave me!" He hugged her gently "I won't." And he took her home. He let her use his shower and get some food "Stay as long as you want." She thanked him.  After learning they could trust each other they spilled theirs lives to each other.
Soundwave became super close to Echo, she was scared to go any where alone. He didn't mind, he loved spending time with her. Soon Echo met Soundwave's friend, Megatronus, who fell in love with the little femme thus began reason IT started.