The Spearmaster and the Black Cat

you do understand that they are not exclusive right? polygamy mean they have multiple romantic partners at once and first time mean he will have his first time having intercourse. that most likely mean he will have his first time with one of his harem members. so while i don't know what about that turned you away i guess keep that in mind.

The problem with jp light novels is that most of the mc are naive and simp, to the point that their brains don't work most of the times when involving women. They have an innate prejudice against women in the fact that if their enemy is a man then they would not hesitate to kill them to avoid future troubles even if that man is weak, on the other hand if the enemy is a woman then they tend to let them go with the thoughts of "she's a woman so once I have a relationship with her then she won't be my enemy anymore", "I already defeated her so she would never be able to deafeat me" and "women/girls are really cute" they tend to forget tha fact that they are in a magical world where even women can get stronger, so in short protags like that are really stpd

a certain magical index

Arifureta...

When does mc get laid?

You came to the wrong place in jp novels no mc ever get laid

Quite early on in this novel lol

It does have both Polygamy and First Time S*x tags, and someone mentioned those two hold true at least.

At first 100 chapter it was interesting but it started to become boring