maybe once he hits teen years, she's the love interest(?)
Thats his sister
A lot of times with manga I've observed they put the main characters and side characters on the front of the separate volumes. Unlike with anime where there is just one cover for the whole series, different volumes will have different covers. The cover mangago went with for this manga is the one for Vol 2, which is of his older sister. I don't know how they go about deciding which picture to put as the main cover or how they change it if they do. I bet the cover for Vol 1 is of the main character and the wolf beast.
The boy isn't dumb. He's a wonderful person. You're overreacting for nothing. The gender of the MC shouldn't matter as long as the story is good.
if the story is going to be about the dumb boy :((