After the Wolf Beast Betrayed Me, He Regretted It

I was frail from childhood.

So my family chose a little wolf beastman to stay by my side.

But the wolf beastman didn't like me.

He only liked my younger sister.

I didn't compete or fight for his attention.

I watched helplessly as the wolf beastman gradually made his way to my sister's side.

I never told him that only I could suppress his beast power.

At last, he caused a terrible disaster.