Season 10 of Isekai Harem Monogatari introduces several new characters, including:

The story follows , an average student who is summoned to a fantasy world by three beautiful women: a swordswoman, a priestess, and an elf. He is hailed as a hero whose unique ability is to dramatically increase the combat power of women through sexual contact. Critical Review (2021 Perspective)

Given that, I will write a on the trends in isekai harem narratives as they stood around 2021, using your title as a hypothetical case study. If you have a specific series in mind, please clarify.

Chapter 3 — Contracts and Complications Three women stepped forward claiming a bond with Kaiya: Mareth the stoic captain (practical, protective), Lys the gentle archivist (wise, teasing), and Aria, a flirtatious storm-sorceress with lightning in her hair (impulsive, dangerous). Each presented a sigil that hummed against Kaiya’s palm. The town expected him to swear allegiance by moonrise. He chose to defer—partly from fear, partly from curiosity. The three grew unusually animated, bickering and bargaining for his attention. Rumors spread: a hero who could unify patrons might break the Pact’s ancient barriers. That idea painted targets on their backs.

Note: By October 2021, the manga had only covered up to early Miria introduction. The WN had 2–3 harem members actively living with MC.

If you are referring to the manga version by Ryuuichi Shidzuki: Volume 10: