Jari Ris'thera

Jari, a high tier god and the god of order, was once well meaning. They were always stoic and serious, but were friendly and polite, although maybe a bit self-absorbed. The other gods generally considered them their leader. They tried to help organize heaven, but never tried to force anyone to abide by their rules as long as people were nice to each other and to them. They knew that gods were people too, but they wanted to prevent eventual chaos with rules. When Armada was created, they were put off by her rowdy nature and wanted to correct it. In Jari's eyes, it was not befitting of a god to act so frivolous. They wanted everything to be perfect and were afraid of Armada challenging their beliefs. In an effort to make themself feel justified, they doubled down on their rules and began enforcing them. Eventually, over many decades, they grew an urge to curb Armada's behavior (along with making sure everyone else acted like a "proper god") and dramatically changed for the worse as their self-absorption turned into something closer to narcissism. Jari took Armada's locket as a punishment and actively antagonized her, all while seeming stoic and uncaring, which Armada obviously hated. Until the day they did something to upset her so much that she challenged them and lost. Armada took back the locket before plummeting to Earth, but Jari didn't want her to have that power.
Eventually, Jari went to earth and pretended to be Armada's friend, trying to drive a wedge between her and Sirius and isolate her so they could fight her. They did the bare minimum to hide their identity, really only trying to wear more "human" clothes. Unfortunately for Jari, Armada, being the god of instinct, knew something was off about Jari all along. She pretended to be oblivious, pretended to hate Sirius, pretended to run away back into the forest with the locket- but only so she could fight Jari alone. She didn't actually get to fight them, though, because when Jari realized they had underestimated Armada as she overflowed with power, they fled with the key. While it may seem uncharacteristic of the overconfident god to flee a fight so easily, their fear of Armada- not just of her strength, but of her rock-solid ideals- overpowered this confidence. Armada still doesn't know anything about her past life, but now she's looking for leads with Sirius based on what little she knows from Jari. Jari still refuses to come to terms with the fact that Armada's existence challenges their perception, and now wants to completely destroy her, especially since she seems to be happy on Earth now. They channel their frustration with themself into their hatred of Armada, but they want to settle their score personally. Unfortunately for them, they don't realize that they're also scared of her. Also, their obsession with perfection starkly contrasts with Armada's distrust of unblemished people. Perhaps even after her memories were erased, Jari's influence made her skeptical of people she percieved as similar.
Jari, obviously since they're a god, has several magic abilities. Like Armada, they are immune to the effects of substances and illness. They can summon and hide their wings at any time, unlike Armada who has to be at full magic power to do so. Jari is also able to shoot hyper-focused beams of pure magic energy, shapeshift (to an extent, since they must remain humanoid), and can heal pretty much any wound (they can't revive the dead, though, as no god can do that).