Question Why having a talented little sister is a must in CN novels?

Why do you think having a talented little sister, a chubby best friend is a must in recent translated novels? Is it just a cliche or for world building?

 

so you can put an incest tag on the novel

Think the chubby friend is to follow the template 'ugly friend to get more focus on handsome MC'

 

Well the chubby best friend is there so the MC has a non-romantic friend that can be interacted with that is no threat for potential love interests.

As for the talented little sister, I think they're just following the JP novel trend.

 

It's a cliche. The fat friend is a foil to the MC. The talented lil sis advances the plot, providing some concrete aim to the MC esp. when she gets kidnapped/taken in by some super sect/cultivator and the MC is forced to get strong to meet up with/rescue her.

 

I think it's just the easiest way to get the attention of a cute female. She's a younger sibling so it comes with pre-built waifu tropes: she's someone to be loved and protected, give out affection, can be rescued for brainless damsel-in-distress arcs, probably loves the MC unconditionally and if you are a pervert there's the JP incest angle that always seems to pop up.

It's like a premade waifu fresh out the bakery with less of the complications of an untamed waifu caught in the wild.

Also something can be said about the authority dynamic between the older male singling and the younger female sibling.

 

There is another name for that chubby friend, FATTY.

 

You missed a vital piece of information- fatty best friend, talented little sister and he has to be Chinese too. The MC halo won’t manifest into invulnerable plot armor without that final piece, I speak from experience as I’ve got 2/3 IRL but I’m not Chinese so...

 

The fat friend is a cliche and it's one that dates back a very long time. Journey to the West is a good example of this, and that book was written in the Ming Dynasty. The little sister thing isn't something that I ever encounter - and of the last twenty or so books I've read, there might only be little sisters in one or two of them. I suspect that it has more to do with writers drawing inspiration from anime more than anything homegrown.