@chilzhul The japanese title uses "maou" not Satan. Which roughly means 'demon lord'. Japanese Authors to not know their English, it's not their job to know. A great example is "Shingeki no Kyojin" Which gets written as "Attack on Titan" Which...is not what that means in Japanese. It means "Attack of Titans" more accurately. (I also shouldn't have to point out the mistake in plural either)
I get that's the title they wrote, and it can be called that. But they're not calling the character 'Satan' in the actual raws to my knowledge, I'm not aware of any furigana saying to read Maou as Satan. (Maybe it's there and I don't know it, but I doubt it).
That's why I'm saying it's a 'localization mistake'. And why I say people shouldn't just follow it, there is a possibility of author just not knowing his English and thinking "Maou" and "Satan" mean the same thing because all the localization companies that make that switch. People are okay with it because it's Satan, but imagine, if a manga had a 'generic' god in it and it got localized as "Allah" or "Jesus" people would be outraged. It's literally the same mistake.
That's why it irks me that scanlators do it.