beta
Both played her either way. The one she helped and fell for (angel ryo) could have simply explained instead of hiding it all and letting his brother (devil ryo) play with her, abuse her. Like that's sick bruh. So she made the perfect move for her and her kids future.
Theory:
Part.1
Sou (angel) was actually ryo(devil) pretending to be sou. So what probably happened was ryo abused Nana then left house for a while and whenever that happened sou would be nicer to her to make up for it. So the day killed him was the same too she probably was left there and she finally had it enough so when sou came she was normal and gave him pills and knocked him up. When "sou" (ryo actually) explained to her how he was the one killing "ryo" (sou actually) he said what happened but using Sou's persona acting all nice n all.
Part.2
I think ryo was the one hiding while sou got to have the life of "ryo" *just. a feeling* ryo resented sou for it ig and probably didn't like his good nature either so he did all this after Nana made a move to probably get registered and have Nana. He probably already knew that by marriage he cld get registered but it wouldn't be possible as long as was still in the picture so he just used her for his own gain and live Sou's life fr but guess what, things didn't go his way lol .