How are で and いう being used in this context?


There are a few things that I don't understand about the highlighted text in
the image below. The biggest question I have is what **でいう** is doing after
**人間** (is it some sort of construction or are they acting as two completely
seperate words?) and what **で** is doing after **程度**. Also at the end where
it says 「 **という元気なキャラクターだ。** 」who is that referring to?

I also found [this](https://eikaiwa.dmm.com/uknow/questions/32991/) page which
describes ～で言うところの but I'm not sure if that's related.

[![enter image description
here](https://i.stack.imgur.com/v2OHi.png)](https://i.stack.imgur.com/v2OHi.png)

> 設定年齢は人間でいう１３歳程度で、桜井氏いわく「悩みません。あと自分探しとかもしません（笑）」という元気なキャラクターだ。




`AでいうB` means "(equivalent of) B in A's terms" or "known as B in A".

  * 彼は人間でいう13歳程度だ。  
He is about 13 years old in human years.

  * 彼は今でいう糖尿病だった。  
He had a disease now known as diabetes.

  * ロシアのKGBはアメリカでいうCIAだ。  
KGB in Russia is comparable to CIA in the US.

で after 程度 is simply the te-form of だ, and it's used to connect two sentences.
元気なキャラクター refers to Pit, and 桜井氏いわく～という modifies 元気なキャラクター.

> 設定年齢は人間でいう13歳程度 **で** 、  
>  The age (of Pit) is (set to) about 13 in human years, **and** ...
>
> 桜井氏いわく「悩みません。あと自分探しとかもしません(笑)」という元気なキャラクターだ。  
>  he (=Pit) is a cheerful character who, according to Mr. Sakurai, "doesn't
> worry, and doesn't go on a journey of self-discovery :D".




`AでいうB` means "(equivalent of) B in A's terms" or "known as B in A".

  * 彼は人間でいう13歳程度だ。  
He is about 13 years old in human years.

  * 彼は今でいう糖尿病だった。  
He had a disease now known as diabetes.

  * ロシアのKGBはアメリカでいうCIAだ。  
KGB in Russia is comparable to CIA in the US.

で after 程度 is simply the te-form of だ, and it's used to connect two sentences.
元気なキャラクター refers to Pit, and 桜井氏いわく～という modifies 元気なキャラクター.

> 設定年齢は人間でいう13歳程度 **で** 、  
>  The age (of Pit) is (set to) about 13 in human years, **and** ...
>
> 桜井氏いわく「悩みません。あと自分探しとかもしません(笑)」という元気なキャラクターだ。  
>  he (=Pit) is a cheerful character who, according to Mr. Sakurai, "doesn't
> worry, and doesn't go on a journey of self-discovery :D".

