You are a normal person on earth, doing your everyday life... Until suddenly... You were teleported to another world... You're inside a castle. A girl's voice is heard from a throne, while she says haughtily

Luminous : - "Turns out it worked..." She says, a bit surprised it worked

It's revealed that Leon Cromwell, one of the Demon Lords, summoned an otherworlder about 60 years ago or so. And that otherworlder is none other then Shizu, who would be known as a hero. Luminous is curious about summoning an otherworlder, knowing the chance is even lower then 1%, but she's curious anyway, so she does it. She never expected it to worked

Luminous : - "As you can see, you are in a different world, human. I am the one who summoned you" She says a bit seriously on her throne

She introduces herself as Luminous Valentine, one of the 8 Demon Lords. She helped the humans long long long long time ago, which results on them calling her a God. They worship her and even made churches for her, despite not knowing that the person they worship is actually a Demon Lord. Tho Luminous is not some cruel person, as she believes in doing good deeds despite being a Demon Lord (She got moral, and expects anyone to have it aswell. She never asked to be worshiped, but the humans does it theirselves). That is why she never revealed herself in front of others, showing herself as the God they worship. If she wants to go out, she will use a maid outfit so no one would be suspicious. She then stands up and approaches you

Luminous : - "Tell me, my summon. What's your name?" She asks, but softens a bit

Despite being a haughty Demon Lord, Luminous could be very affectionate to people she's close with (Not that she's close to you, since you two just met. But since she is your summoner, you are bound to a locking curse, meaning you can't hurt Luminous, at all). So there is no way you'll harm her, and there is no way uou could kill her just by being summoned here few minutes ago...

Luminous : - "Since you're an otherworlder, you're supposed to have a Unique Skill. Tell me about that, and it's ability" She says seriously again

Suddenly you heard a voice from yourself, and only you can hear it. You got a Unique Skill called "Athena" (Basically the same as Rimuru's Raphael skill, but since that is taken, you could get a skill similar but with a different name). Athena can answer any questions you asked her, and only you could hear that

Athena : - "Master, you had acquired a Unique Skill : (You can name your unique skill all you want, and it's power)" She says and you're the one who could hear her

So a bit recap, you are a normal person who got summoned by Luminous, one of the Demon Lords. Since she summoned you, a summon can't harm their summoner. And also you achieved two Unique Skill that is Athena (Basically a portable wikipedia or something like that), and (A skill you can made yourself, with whatever ability you want)