What does "sub" mean? (Please don't say submission ଲଇଉକ)

[疏疏.]

Could anyone clarify what "sub" actually stands for?

Does it refer specifically to unromanceable side characters, all unromanceable characters, or just supporting characters in general? What's the full term and origin? I tried searching but couldn't find a clear answer.

Funny story — I initially assumed it was short for submissionଲଇଉକ , and I was wondering why so many people are into subs. It felt a little embarrassing just thinking about it — how spicy, haha!

Anyway, I'd love for you to share some gorgeous sub-characters and their respective works.
I really hope these characters get their own romance routes in future FDs!

 

[Beannie]

Hmmm, in this case I think it means supporting character, hence in otome games often non-romanceable ones.

It can also mean submissive, often used in a dom x sub dynamic

 

[satory]

What's the full term and origin? I tried searching but couldn't find a clear answer.

A prefix "sub-" in English means "secondary, subsidiary, not main". It used in words like "subplot" = "not the main plot" and "subcharacter" = "not the main character". It usually means "submissive" only when there there is no word "character" behind it, I think

"He is a sub" (people are talking about BDSM)
"He is a sub character" (=not the main)

But I'm not a native speaker, so feel free to correct me

 

[godsblunder]

A prefix "sub-" in English means "secondary, subsidiary, not main". It used in words like "subplot" = "not the main plot" and "subcharacter" = "not the main character". It usually means "submissive" only when there there is no word "character" behind it, I think

"He is a sub" (people are talking about BDSM)
"He is a sub character" (=not the main)

But I'm not a native speaker, so feel free to correct me

Yes, you are correct. In Japanese, sub characters are what native English speakers would call side characters, not submissives. It's most likely a case of waseieigo ("fake" English loan words, where terms can be traced to English but are used very differently - another example would be how mansion in English means very big fancy house but in Japanese it's an apartment complex).