That's the beauty of it, every race can fit every style when you stretch it hard enough.
But some races can benefit more from certain styles.
Lunargoth pairs well with Kiihakai because you get to learn Runes early on. Kitsune is another good option as that's clearly some way intended with how both Kitsune we've seen so far being Kiihakai.
Human pairs well with Akakiru because you can easily do a high Honour run with human and you can be seemlessly accepted by the Bladed Lands, who are racist.
Oni pairs well with Aoyusumu because you can have the most benefits from doing an Aoyusumu Demonic Cultivation run. Even if you don't do Demonic Cultivation, you can still benefit from being an Oni later on as the game checks whether your an Oni if you have Aoyosumu style.
Yokai pairs well with Midorikatai because you have beastly ancestry and can have an easier time with the animalistic side of Midorikatai. This is especially the case for Bull and Monkey Yokai. Oni can also work because you can either become Hulk with the green Spiritbrand or embrace your inner Asura and become a real Heavenly Demon, as was intended by your ancestry.
Human can also work for Kurokonton as it synchronizes with Merchant Background. Kitsune pairs well with that style as Anon is somewhat inspired by Naruto when making that style, and so has included certain benefits for Kitsune.
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