Sonya Baelz (ソーニャ・ベルツ) is a military officer of the Crossbell Guardian Force. She serves as a deputy commander at Tangram Gate in Zero no Kiseki, and is then promoted to commander at Bellguard Gate in Ao no Kiseki.
Sonya embodies the perfect persona of a high-ranking military official. Strict, punctual, calm and sharp, she oversees military operations at Tangram Gate in Zero no Kiseki. As the commander directly in charge of Noel Seeker, Sonya and Noel are often seen working together during scenes in both Zero and Ao no Kiseki. Sonya also coordinates Crossbell security operations with Sergei Lou which causes both her and Noel to get involved with the Special Support Section and their missions.
It is revealed that Sonya was the one who recommended Randy Orlando to the SSS and that Randy acknowledges her as a frighteningly efficient officer.
After the declaration of the Independent State of Crossbell, Sonya's rank was transferred to commander of the newly created Crossbell Defense Force. When chairman Henry MacDowell declared the independence as illegitimate and meeting with Lloyd and the SSS, Sonya decided to take a neutral stance which would allow her to act in Crossbell's best interests by assessing all sides of the situation before exerting any military force.