What hints? Up until she overheard her parents talking about how Abel didn't want to marry her, she only exhibited signs of being a "brocon" (to borrow Japanese terminology), which is not strongly correlated with actual incest or yandere-ness (even if brocons can "evolve" into either one of those two).I love the fact that the Yandere side of the sister has been hinted for a while
... Literally the second setence of that comment invalidates the first one and last three.Yandere sis clearly existed before he ran. She knew he was going to run. She acted before he ran and sabotaged the truck. Him running away did not make her into a yandere. She was one already. He didn't cause her any psychological harm in running.