Despite her fervent loyalty towards Rose, the player finds out during her battle that she has a full team of beautiful-looking Pokemon ala Lusamine, until she reveals at the very end she uses a Garbodor of all things, which doesn't fit at all with her team's theme, because she herself states it's the one Pokemon who stuck with her before "she changed her image." The simple revelation tells us that, for all her blind loyalty towards Rose, she's a human in her own way. You don't need a complicated storyline to shed light on a person's backstory.
While Twilight Wings may not be an official extension, it pretty much gives a very good idea on Oleana's motivations and how different she was before Rose saw the potential in her before properly rising to stardom.
...Instead, the anime makes her so bland that they're sticking her with a Milotic and gave G-Max Garbodor to an extremely useless subordinate unrelated to the picture. I'm starting to think all those improper G-Max debuts from randoms instead of the actual Gym Leaders do rob their proper debuts under the Gym Leaders.
I'm probably being a bit too quick to judge since we're halfway through the arc...but the fact they did the above like that takes off a lot of points from portraying Oleana right because they literally threw her real ace who made her into a proper human out the window.