Bethany Illéa (née Schreave) is a historical character and was only mentioned in The Elite.
Bethany was the wife of Gregory Illéa, founder of the nation Illéa. She became the first queen of Illéa and was said to have purposely killed herself upon Gregory getting all his power as king. It can be assumed Gregory changed so much that she didn't want to be his wife, but wasn't allowed to divorce him. So, she might have purposefully committed suicide.
America described her in a picture as a "beautiful woman but the luster had gone out of her eyes".