So the third part of dev interview aka the Blacksouls part came out, but for some reasons DLsite decided to split this part to yet another two parts... I'm not going to post the link, you can find it in Toro's Twitter if you are interested. Here I'm just going to summarize stuffs that I found interesting.
I found this last one particularly interesting. After some researches I finally get the answer
which is why it took me so long to post this. Just so you know that the conclusion is indeed very simple; it's nothing mindblowing and it's what many people expected, but what's interesting is how this conclusion is led.