

Edit:

I found this to be called: [Not blood
Related](http://tvtropes.org/pmwiki/pmwiki.php/Main/NotBloodSiblings)
according to an article in TVTropes.

here are some examples:

> In the anime Happy Lesson, Chitose's sisters aren't really related to him
> and are clearly invoking a Big Sister Instinct and Cool Big Sis.
>
> KissXsis runs on this trope. Keita's twin step-sisters compete with each
> other for his affections, much to his dismay. His parents not only are aware
> of this, but actively encourage him to go for one of the girls, constantly
> reminding him that ' **it's not by blood, so it's OK!'**

In KissxSis, Ako and Riko literally loves their little brother Keita (related
by marriage of their mother and keita's father) and they keep competing for
his _Love_ on almost every episode.

Freezing also has this, a 2nd year Pandora has to choose a 1st year limiter..
eventhough the limiter calls his pandora a sister (but not blood related) they
perform an initiation "baptism" or also know as "first room visit"

Other examples: kanokon

Who started this? and what is its inspiration?


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2016-03-09T11:59:26.070
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2016-03-14T01:49:32.967
2016-03-14T01:49:32.967
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question
tropes
Where did the elder sister/s little brother love affair started