Kyōkai no Kanata supporting characters
Also check out our detailed explanations of Akihito and Mirai!
Nase Mitsuki-INTP Mitsuki is one of the few characters in the series that can both understand and keep up with Akihito’s thought process, mostly because they share functions just stacked differently. Much of Mitsuki’s banter with Akihito assumes his ability to understand the basis for her arguments without her having to explain them (Ti) and several times she gives him only the information he needs to piece together a picture of the situation as she did (Ne). She tends to use Si to enhance her demonstrations of Ti by calling on internally cataloged information and sources, making her decisions more well-rounded and less susceptible to potential fallacies. Her only real uses of Fe, which she often ignores and even makes fun of with her blatant disregard and scorn for what people around her want and expect from her, are when she wants her brother to do something, and so complies with his simple wishes to convince him.
Nase Izumi-INTJ Izumi is a classic INTJ and one of the most well-balanced (and scariest) characters in the series. She operates quietly and only when necessary, and she always has a plan that she formulates far ahead of time in anticipation of how events will unfold. She plans this way based on vast stores of static information in her head that she collects almost unconsciously. Her Fi manifests in conjunction with her Ni to help predict how the people affected by her plans will react to their respective environments and adjust her own actions accordingly. Her grim sense of self-confidence stems from development of her inferior Se, which motivates her to act (as opposed to trying to predict everything and getting lost in doubt through Ni) as soon as it is practical to do so.
Shindō Ayaka-ISTJ Initially I thought Ayaka was an ISTP because of how much she logically justified things to herself, which looked like Ti. I was wrong mostly because she justifies things to herself based on what she sees and experiences, and uses logic and internal sets of facts to explain things to others. Her explanation style makes her an excellent character for the scriptwriters to use to describe important facts that don’t come up in the normal course of things. Like what exactly the Hollow Shadow is, or the Calm, or how the local exterminators deal with Akihito’s demon half. Her clearest use of Fi is probably when she meets Mirai and immediately tells her not to attack before Mirai had even introduced herself. Aya’s weak Ne tends to forget about important changes or omit some related information when she explains things, like changing the barrier outside her shop and getting Mirai lost, or “forgetting” to tell Mirai that the fruit demon sprayed nasty smelling liquid.
Nase Hiro’omi-ENTJ Hiro'omi is the classic smart-ass ENTJ. He is picky about seemingly random little details, like Mitsuki calling him onee-chan, and rarely if ever feels obligated to explain information he considers obvious, characteristic of many Te-dominants. His auxiliary Ni, however, while perfectly easy to understand for him is nearly impossible for anyone else, except maybe Izumi, to follow. It is all the more irritiating when paired with his slowly maturing Se, which makes him more willing to act on his strange impulses, including holding Akihito's waist, being openly incestual, and asking Izumi about his hunches about Mirai and Beyond the Boundary. His Ni also lets him keep up with everyone else, mainly Akihito's unwarned ventures with Mirai. Most of his serious Fi, that is outside of his idolizing Mitsuki and feeding his ego by making Akihito beg for information, comes out after Izumi's full plan comes to light. His ethical values, usually taken for granted, are so blatantly violated by Izumi's actions that he chooses to speak out against her, before thinking that he himself may be biased towards Akihito and Mirai, and against the general good.