Tatsumi-san (たつみさん , Tatsumi-san) is chapter 139 of the Beelzebub manga.
Summary[]
The next day after the battle with the Akumano Academy, Tatsumi Oga walks in his bedroom to discover that Hilda has awakened. However, she shows no sign of remembering anything.
Oga informs of her amnesia to his family. His family is quick to put the blame on Oga and he muses that no matter how the situation is interpreted, he would need to fix her amnesia or he would be stuck feeling guilty. Oga's family reintroduce themselves to Hilda and explains that she is Beel's mother and Oga's wife. Hilda then blushes and asks what a wife is.
Later, they all watch a show that demonstrates the characteristics of a wife. Hilda assures that she is now aware of the fundamentals of a wife and acknowledges "Tatsumi" as her husband. She then affectionally addresses Beel as her child and takes care of him.
Eventually, Oga falls asleep on his bed and wakes up to find Hilda sleeping beside him. Bewildered, he makes a commotion. Hilda questions this since they are a family and Oga argues that is inappropriate as she had always slept with Misaki. Hilda approaches him and asks what is it about her that he does not like. Pushed to his limits, Oga runs away from his house with Beel, shouting that this is not the Hilda he knows.