Can i use anothers stories invented charatere term?

I wasent sure where to post this, sorry @Sydney_H but it legit wouldn’t let me post other places then community I got no idea why

screenshot for prof I could only pick community

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anyway to my actual post. I want my mane character in my story to be a slay vega, not from the start its a thing she finds out later. it was a team I first heard in the anime ancient magus bride really recommend its a kind of spellcaster,

but when I looked it up to learn more about slay vegathough in the English translate they changed it to Sleigh Beggy and if I didnt misunderstood that means . I found out its and original thing the author of the ancient magus bride created. so I dont know if I am allowed to use it. would it be different for all the stories there copy the popular vampire and werewolf stories all the time, dont tell me they have existed in forever, the making love interest is only a 20-year-old trend before that they were monsters

if it depends on how much I will use it, not a lot. I plan to let her find out towards the end of the story.

I’m not quite sure I understand, but I think it’s best to avoid using another writer’s creations even if just a small term.

It’s apart of their universe and it can cause a lot of distress to a writer, especially if credit is given to someone else.