Q: I agree with you whole heartedly demon とはどういう意味ですか?Gene・Simmonsが大統領選のことについて、友人や知人に話すなとTwitterで言った時に、アメリカ人がリプしてこう言ったのです。悪い意味なんでしょうか? とはどういう意味ですか?
A: Gene Simmons plays a demon in his band named KISS and the person agrees with him.
Q: I faced my demons とはどういう意味ですか?
A: when someone says they faced their demons, it's a way to express they finally acknowledged their problem they've been having.

for example if someone said that they were afraid of telling the truth but decided to face their demons it means they decided to confront their problem.
Q: demons とはどういう意味ですか?
Q: "You got your demons and they all look like me" とはどういう意味ですか?
A: NordicRest is correct. However, I would like to add:

That quote has a self loathing tone on part of the speaker. The speaker feels bad and wants pity.

That is not always a bad thing, but be worried if someone says it to you who is a native speaker of English.


Q: demon と devil はどう違いますか?
A: demon = an evil spirit

the devil = the boss of all the demons (the devil is also called Satan or Lucifer)
Q: demon と devil はどう違いますか?
A: They are the same. Just different ways to say it
Q: hang-up と inner demon はどう違いますか?
A: A hang-up is something very minor. An 'inner demon' is worded much stronger and sounds like a serious problem.


Q: demon's sweatheart は 英語 (アメリカ) で何と言いますか?
A: QAの全文をご確認ください
Q: demon は 英語 (アメリカ) で何と言いますか?
A: QAの全文をご確認ください
Q: demon は 英語 (イギリス) で何と言いますか?
A: QAの全文をご確認ください
Q: demon は 英語 (アメリカ) で何と言いますか?


Q: "Before dying, I made the demon king the 1000th sacrifice"

(also, do I have to capitalize "demon king"?)

A: Unless his/her name is demon king, no capitalization needed
Q: Now, I'm to gather the demon aristocracy at the gates.

I've met this sentence in TV series and was confused why am to??? この表現は自然ですか?
A: TO BE TO is used to give someone instructions or orders. Let’s say a father lets his daughter go on vacation with her friend’s family for a week. He tells her “you can go with them, but you’re to call me every day.“ this means that she can go, but he’s ordering her as her father to call him every day while she’s away.
Q: When the snail-eating demon was overwhelmed and defeated,the gloom dispersed. この表現は自然ですか?
A: Sounds good, but why does the demon eat snails?
Q: We know that demons and angels coexist in our mind. And we have to choose whether to show the angel's heart or demon's heart to other people every moment. And then with our interaction we will make our relationship and karma. この表現は自然ですか?
A: We know that demons and angels coexist in our mind. And we have to choose whether to show one or the other to every person we meet, and that will be what forms our relationship and brings karma.

By karma, do you only mean bad karma?
Q: A demon got into him.
He got a demon into him. この表現は自然ですか?
A: If the demon is taking full control, then English actually has a word for that, it's "possessed." To be possessed is to be moved by a strong feeling, madness, or supernatural power (like a demon).

A demon possessed him.
He was possessed by a demon.

If the demon is not taking control, but literally jumping inside of him, then both are correct. But they make the demon sound really small, small enough to jump inside a person's body.

Hope that helps.