Senken no Majutsushi to Yobareta Kenshi - Ch. 28

[zerio]

It was covered or at least implied from his flashbacks since I haven't read any other adaptation.
Edit: after skimming previous chapters it seems to be strongly implied. Chapter 19 is about that past with the image of his twin sister at the end. Chapter 20 page 28 has the image of the goddess followed by the image of the person he wants revenge of implying they are the same. I do remember him implying that the goddess used to be a human. Lastly there is the story of why the goddess hates twins which is because twins injured her (chapter 1 page 35). I'm mostly going by memory though so unless I completely re-read I can't give the complete explanation as to why It's implied as strongly as I remember it being.

I just reread, and some of what you said isn't quite right. First of all, it's not yet a fact that he has a twin, nor have they implied that he has one. The black haired woman in ch 18 and 19 doesn't look the same as him. The ones who are twins are likely his comrades in his mercenary group, which are the guys on the bottom right.

Now, I also think that the "goddess" was someone from his world and the enemy of his mercenary group (some kind of evil queen?). But he never said/implied that the goddess used to be human.
Although in ch 20 and 27, we saw the image of the goddess followed by the evil queen, so it's probably somewhat true.
Also his leader has the same name as the evil god (ch 19 pg 22 and ch 1 pg 36), and his mercenary group has twins.

My theory was the divine war mentioned in ch 1 was actually just a war between his mercenary group vs evil queen. My guess was this world came to be as a result of this evil queen's power, hence she became the goddess.
And somehow MC got pulled into this world. That's why he viewed the goddess as his enemy. And the twin guys were powerful that the goddess made them taboo.

But none of this has been confirmed, so saying this is a fact is wrong.

There is also the fact that his party is the reason twins became "evil" since he and his twin fought this "goddess" in a war in time immemorial and injured her.

 

[llde]

Honestly Angie was in total cognitive dissonance. How can you fucking believe that a benevolent god would course someone for life, to shoulder sins they didn't even commit? How can you say to a girl cursed to kill, while dying yourself, to keep praying to so that the god can remove the curse (they putted on the first instance), in some sort implying they didn't pray enough, so it's their fault the curse is still there.
Karen apostate mindset is WAY more logical.