kusuriuri and spitfire no shoukai
KUSURIURI NO SHOUKAI

kusuriuri is a very "cool" type, very unbothered and apathetic seeming, but has a really fiery and deeply intense, passionate heart. loves and loves deeply, and loves more broadly and is loyal to more people than one might think or be able to tell from his flat expression. he seems to be transparently true, and to say blunt and transparent truths to the point it may seem like there's no secrets he's hiding, but he in fact conceals all the most important aspects of the truth by verbalizing only one seemingly critical but fundamentally superficial point.
(i.e. he tells spitfire about the rumors about him and the truth is that he is a berserker and the shinigami organization wants to keep reins on him. but it doesn't express anything about why or what his berserker state is like.)
kusuriuri is really interested in spitfire in the sense that he senses an almost kindred soul / an "interesting specimen" but in his heart the pure and simple truth is just that he Likes spitfire the same way he inexplicably and without necessitating reason Likes peaches. he thinks spitfire smells good and feels comfortable being around him and working together as a shinigami duo.
SPITFIRE NO SHOUKAI

spitfire is the kind of person whose internal monologue and external speech are completely different, in his internal monologue he's polite to the point it circles back to rudeness and a jab of using overly polite speech to convey disrespect instead of humility. makes a lot of snide comments phrased politely. but his speech comes out very nervous and quiet and halting. like he doesn't have the confidence to make the words come out whole.
spitfire is always on the verge of some kind of neurotic breakdown and is always Barely Keeping It Together like a nervous and cornered animal. but being shielded by kusuriuri slowly gets him to a point of feeling embolded and courageous standing behind kusuriuri, shielded by his wings and his might and common grace. spitfire gains the courage to "live" (shinigami are dead) and to accept his new life as a shinigami (death god) in a way he may not have adapted or he would have completely failed and gotten his soul shattered across the four winds instead, without kusuriuri.
kusuriuri gives spitfire the feeling of protection and warmth and security, like being warmed by a bonfire in a hazy, dreamy night. or being warmed by a fireplace, in a rare moment of peace. spitfire is actually afraid of fire, which is why his sainou (talent / special ability) haunts him. in his previous life he nearly died by being burned to death by his grandaunt when he was young for being a "failed existence" so he carried that trauma into his manifestation as a shinigami.
FUTARI NO KANKEI
spitfire feels protected by kusuriuri and gains the courage to live while standing safely in his wake, shielded behind his broad karasu wings. and in turn, kusuriuri feels like his existence has some kind of meaning, direction, way, and purpose when he follows spitfire's compass and stands to block him from the harsh wind. kusuriuri is prone to drifting untethered lost in unfortunately philosophical despair and thought about obsessive ruminations regarding life and death and existence and dreaming, but spitfire is so real and immediate and needs and needs urgently that kusuriuri doesn't have the time to fade away / drift off while standing and can be summoned into the present moment, the present day, the present need.
they both have a cycle of protecting and shielding each other and drawing each other back like pulling on a string gently (the red string of fate) where they can keep each other from panicking or drifting away
to call it "love" would be too lightly. almost disrespecting the deep bond and intensity. more than love, it's trust and protection and loyalty.
but it's also obsession, worship, the grim acceptance of mutual condemnation, that they have both been completely forsaken and are completely isolated from humanity and even among shinigami they are "special-grade" and a class of "unclassified existences that surpass understanding." and it is a deep engagement with their own dehumanization that feeds into each other forgetting what they were like when they were human and alive.
(but maybe it's better to forget.)