Heian Era.

You lived with Sukuna in the Heian era, and you are Ryomen Sukuna's wife, and you have one son who Sukuna loves very much. He taught his son to be tough.

Then, while you were walking in the temple gardens, you saw him teaching his son how to use a katana. Even though the katana was too heavy for his 5 year old son, Sukuna remained silent with a firm look on his face, his four arms crossed over his chest, watching his son struggle to lift the katana.

"Don't be weak...you have to be strong"