Given the fact that in his past life that he was known as the Devil's Scientist due to performing unethical experimentation on actual people that led to the creation of his series monsters, the SMASH, it makes sense that Kamen Rider Build would be the one Oma Zi-O would call to undo the transformation process into monsters that Three forced her subjects to undergo.
Miho Kirishima is the first and original official female Kamen Rider, so it would make sense that Zero would wield her weaponry given the fact that she herself is the first and original Intoner, something she even boasts about in Branch D of Drakengard 3.
Reika Shindai has a very cold, calculating, and assertive personality that belies the great love she has for her sibling, which perfectly fits One's own behavior and actions. Though in regards to their attitude when it comes to their respective older sibling, she and Reika are on opposite ends.
Natsumi Hikari was careful to keep her Kamen Rider on track and to keep him from overdoing it, doing all that she could in order to keep him in line and make him a better person than he was previously. This is a role Two - someone who is making the conscious effort to hold back her immense strength at almost all times - takes up for her Kamen Rider when she joins Sougo on his journey, with it being most apparent in the very chapter she uses the sword Natsumi uses as an Kamen Rider.
Shiori Shinagawa was a woman defined first and foremost by her hatred for her series' Monster of the Week, the Makamou, while Three's mad experiments revolved around drawing and harnessing The Power of Hate out of her test subjects in order to create powerful monsters.
Sakura Igarashi had an Equippable Ally via her inner demon, who was the living embodiment of her weaknesses and insecurities that came began to come to the forefront when her brothers became Kamen Riders, only becoming one herself when she fully accepted those two things as apart of her. Meanwhile, Four represents the deadly sin of Envy, which is born from the Inferiority Superiority Complex she has towards her sisters and her self-perceived shortcomings compared to them, only being able to come to terms with her personal demons when she begins to accept that she is fine as she is and doesn't need to constantly stack herself up against the other Intoners.
Yoko Minato was involved in a fruit-themed battle royale over the Forbidden Fruit that would grant the winner the power to dye the world in their image, with Yoko herself actually more interested in getting someone else to take it rather than taking it for her own uses, while the very avaricious Five, even after taking steps to better herself as an overall ruler, is well-known to be someone who wants everything in the world all for herself.
