Yeah, it really is a sad fate for Beato. It really took Ange dying to get either of them to play seriously near the end there. A lot of the bitterness and anger she held pretty much exhausted and became sadness and hopelessness right before Battler ended her life.
Seeing her as a lifeless doll in episode 5 was one of the most depressing things in the entire visual novel. Pretty much just sitting around to be finished off for good. All brought into this state by battler, who completely destroyed her at the end of Alliance. It doesn’t help that Bernkastel and Erika are also running around wanting to completely destroy her too. This isn’t even getting into the horrible life she’s had as Yasu.