Darken Theory (Besides Varus, Jax, etc.)
So their was a theory that the Darken are living weapons or are corrupted/created by living weapons. Varus was one idea, which I think was the only viable candidate. But! Couldn't Sona have such a "living" weapon. Etwahl I think it is spelled. So Etwahl killed Sona's mother, something violent but not something Aatrox would do, aatrox likes battle more than murder. The weapon can slice things from a distance and is magic. In her lore it kept reappering when the orphanage tried to sell it, it floats, can slice things from distance, can cast the spells that are in game, and seem to actually control people's emotions. But so far this is just another magic weapon like Ezreal's amulet. The difference is in Sona's Judgment the weapon has emotions, takes certain actions such as trying to play itself, resisting Sona, stiffening, etc. Its even like a drug. "She felt no fear so long as the etwahl was in her grasp. Her arms curled lovingly around the instrument, her fingers expertly trailing along the hammered brass and taut strings. Pressing it against her cheek, she closed her eyes and waited. It was at times like this that she could feel the instrument alive in her arms, taking slow and measured breaths as it guarded its master." Notice she can tell its alive and loves the Etwahl even after it killed her mother. May it also be that when Sona acquired the Etwahl it took her voice away? Maybe she was born to be a singer, yet the Etwahl took the gift away and now can play beautifull music?
All speculation and much of it is very stretched. Just brainstorming. I'd love to hear some other ideas and theories.
-Arakadia