How Trina connects to the children of Marika and Radagon being the microcosm of Marika's story
So, we already know that Malenia is younger sister of Miquella, as revealed by the Japanese script reference:
^ From Malenia's script in Japanese ( x ), 兄様 (anisama), 兄 (ani) = older brother and 様 (-sama) is respectful form to refer a superior that is how Malenia views and treats Miquella
^ From Miquella's cut dialogue ( x ), 妹 (imōto) = little sister!
However, as for Trina? She views Miquella as the younger one, referencing him as 'that child', in almost motherly manner ( x ):
あの子を、神にしないで…
…あの子にとって、神は牢獄
あの子を、許してあげて…
あの子 (a no ko) = that child!
This would be strange if it was only connected to Miquella's curse, considering that we find Trina herself very child-like and as Miquella's other self she'd be expected to inherit the eternal youth curse, right? But it seems like Trina, in fact, didn't fully share the curse with Miquella!
The St. Trina's Torch, found in Consecrated Snowfield which is the path to Miquella's Haligtree, depicts her as an adult, and her trailer depiction shows more mature proportions than how we find her!
At the same time Trina and Miquella were already together as one being when she was young enough to be confused with Miquella, who always was just a child physically!
Marika and Radagon were capable of having separate bodies somewhat despite being one person, so maybe Trina's age inconsistency has to do with it? I do not believe that either Radagon or Trina existed as separate people and simply merged with their respective Empyreans, of course! For example, Radagon already proves it was not the case! His Japanese title reveals that he is not just a follower of the Golden Order, but he IS the Golden Order:
= (the) Golden Order, Radagon. Golden Order only exists as the specific Marika's version of the Elden Ring (a version with Destined Death removed) and her will for the laws of nature as the new and only God! Radagon came to exist after her ascension, as Golden Order in a human form! I think as a parallel to this duality, Trina should also exist as always a part of the dynamics and not someone just found and accepted.
However, whereas Marika is two people, the triplets are... well, three people. And this is very important part because Marika is also three people but in a subtle way! This is where we're finally getting to my main point!
Trina, as you can see, reverts to a child after having been discarded, which might be interpreted that Miquella somehow abandoned his eternal youth curse by placing it on her...
However, the problem with this is that Miquella's eternal childhood curse is connected with Marika's will, and thus, with the gold! Marika, titling herself as Eternal, the one who removed literal death from the laws of nature themselves, the one that started war on the Giants due to their flame being an anathema to the Erdtree one day destined to burn it, the one that was terrified of Messmer's flame and Base Serpent from lightless abyss for the same reason, the one that damned the Nomads over just a rumour of their worship of Frenzied Flame, clearly wanted the age of eternal life and immortality! Miquella, the shining golden eternally physically young child, is golden as the reflection of this eternally pure, deathless and radiant existence that Marika wanted!
Trina would not take away his curse (or should it be seen as being too blessed instead?) without also taking away his pale golden light! Instead, she could have shared the curse with him only in some capacity as being born as a part of him and losing privilege of walking around as an adult-ish woman after coming in near-coma state upon being severed from him, or simply reverting to a child due to becoming a flower!
But that is not all there is to her. Whereas Miquella reflects Marika's ascended state and the eternal life for self and her world that she wanted, Trina instead reflects pre-ascension Marika!
A curious part of Trina's nature is her white hair, that only appears purple due to the purple flower nectar dripping from her mostly-flower body! But you know who else had white hair?
Marika herself before her ascension!!!
I went more in depth about why she is not a blonde in this ( x ) post, but basically; her hair is specifically blessed gold, not blond! The Shamans are shown to have grey/white hair and same is true for corporeal versions of the Black Knives that are themselves the same species as Marika:
Trina is also associated with the bodies of water and night; something Numen were commonly associated with themselves since their cities were already built around this aesthetic before being damned underground by the Greater Will!
We do not know of what the Shamans were associated with before Marika basked the village with golden light besides their strong spiritual attunement and their ability to contact the dead as 巫子 (Itako)! Itako are Shinto priestesses, believed to contact the spirits, the dead and even the deities! They are supposed to be blind, too, and notice how the Shamans are wearing the blindfold! Also works with how Marika and her clan first set foot in the Land of Shadow, which is itself the land of the spirits and the death!
I would also argue that Larval Tears were actually already a creation of the Shamans, who ARE Numen, and Nox are also Numen, and although they created silver Larva Tears in mimicry there were the "original" ones assuming the cold green hue instead that is associated with the spiritual and being between the world of life and dead (do not confuse with warm green that is associated with forged grace of gold!):
Now, Trina has an interesting parallel with this as well! St. Trina's Torch, for one, depicts her eyes completely obscured by the hair, showing just the symbolic "third eye" placed far above where even a cyclopic eye would be! To communicate with her right now you must quite literally die, which is not total for the Tarnished always forced back to life (until Two Fingers deem them useless) but you do die after drinking her nectar. She was also discarded specifically in the large ancient gravesite and there granted peace and respite to the disturbed death, which is how Putrescence Knight became her warrior!
Trina's Lily typically grows in the bodies of water as well, and some crabs that feed on it develop the ability to use her sleep magic! You might remember a single crab like this in Raya Lucaria but they are also met in Nightreign! Maris also offers some insight on it, being a version of the Elden Beast that is instead watery and inflicts sleep! And, of course, marine creatures in Elden Ring are associated with the death likewise:
(Disclaimer: Nightreign lore always also counts; Nightreign doesn't have different worldbuilding, only different events after the Shattering!)
Spirit Jellyfish near Apostate's Derelict also drop Trina's Lilies!
Now, we are not sure how much Marika and the Shamans are connected with the water, but we know her other fellow Numen that became the Nox are very much connected with it! Water + Sleep + Cold color spectrum + Death + Spirits are a tie in the lore though, and being connected to one becomes connected with the other in some ways!
Aside of Trina, Marika's family features at least two other Demigod children that were closer connected with this heritage; a Walking Mausoleum deep in Liurnia's lake (the two bell-less ones are not for Demigods but for in-laws, as they lack the Mausoleum Warriors and only duplicate non-Demigod ashes ( x )) and one near the "nameless" Eternal City walking close to Godwyn's grave! Her family includes variety of heritages; the golden Demigods, the redhead Demigods, the 'crucible' Demigods (like Godefroy, Godrick and his five young children that have grey hair like Godfrey regardless of age)... and these spiritual-watery-hidden aspect Demigods like Trina and those other two never met children! (honestly Rennala's black haired genes deserved SO much better...)
Basically? Trina, Miquella and Malenia are a perfect trifecta reflecting Marika's life and story! Trina is a reflection of Marika's past as just a spiritual Numen Shaman woman, and Miquella took over and overshadowed her as a reflection of Marika's ascension into Godhood! Marika's previous self got strongly repressed by her new duty, and even Trina is aware that Godhood is a trap akin to a fate worse than death! Trina was technically born first but Miquella was meant to eclipse her from the very start! @swallowtail-ageha once suggested that they were triplets and Miquella consumed Trina in the womb (it does happen in real life pregnancies too) and I believe it at this rate!
Worth to note that Miquella also has his father's orange eyes! Radagon's eye scar seals are orange, unlike Marika's which are just golden! Miquella reflects not only Marika's former self being discarded for the Godhood, but also her being trapped as the one with the Golden Order itself!
But at the same time, Malenia is the one that reflects Radagon himself!
It is implied that Radagon is the one that "took the shot" for Marika when she got cursed by the Giants! Maleinia is the twin that inherited a very specific curse that contradicts Marika's order, representing endless decay and stagnation of water!
Malenia and Radagon are both this red-haired natural counterpart that warded off the curse from their empyrean by taking it on themselves, willingly or not! Not only that, but a counterpart that strongly lacks the agency and depends on the will and the help of Miquella and Marika respectively! Both only wish to fight for what their counterpart wished! In Radagon's case, he even continued even after Marika absolutely changed her mind on it!
Miquella went further than even Marika had, though... Marika metaphorically buried her former Shaman self with the farevell ritual and the promise, leaving her braid to the Grandmother and basking the village in gold. That young traumatized woman had to go, for the sake of greater purpose to build the new world devoid of all Marika deemed bad for the "better future" she wanted to build. But Miquella buried Trina, representative of the innocense and simpler, more human self, literally.
He did not make sad peace and goodbye with this part of self like Marika but severed it, and with it the same humanity that one day allowed even Marika herself to see the fault and futility of her ways and destroy her own Order. And Malenia and Radagon both... well, they just continue to exist for the sake of something that won't ever be again.
