Even if DOA was about the ninja's, you relate Honoka to a ninja, you put them in side games that interacts her more w/ Ryu, Kasumi, and others and dive into their lore and you have DOAX prioritize the women and showcase them even more, and it's no wonder they were popular, then you make them primary characters in the sequel, especially in a game that mainly prioritizes it's women outside of Ryu and maybe Hayate.