I'm not sure if we'll ever get to see Callum connecting to all of the Arcanums and explaining them to us. Here's me trying to attempt such a feat:
First off, Sky: Skyline elves are very independently focused. We meet Nyx and she's trying to steal the good deed from under them and get a reward, next she's trying to save her own hide. We meet Ibis, when times get tough he suggests the heroes protect themselves and zym rather than protect the queen. A skywing Dragon guard in the past opted to flee when the chips were down, and suroh's family in blood moon huntress told him to focus more on his own safety.
The sky Arcanum is about understanding how the sky and it's power constantly surrounds you, and you constantly weild it just by breathing. It's power is at your fingertips and you can decide how to use it, you are in control of your own destiny. Basically it's "the sky is the limit." It's freedom, as it is said that 'those who discover flight wish to escape back to the sky.'
Next Ocean: We don't meet many tidebound elves and don't spend much time with them. What we know of Finnegran, he desires freedom and fears what he can't control. This makes him a villain in this sense. As for Akkiyu, she tries to trick them into thinking their task is pointless, and when discovered she knows too much, begs for an alternative. Akkiyu must've felt that nothing would stop this group, not even her defiance. So she did all she could to hinder their path, as she knew she couldn't stop them on her own.
Ocean is about understanding their are depths of knowledge that can't be known, and that the Ocean is too vast and powerful to control. The ocean is about working with the waves, not controlling them. It's about trust and faith, about "going with the flow of the tide," taking things as they are. Sailors like being on the sea because they like going wherever it takes them. It's acceptance of the unknown.
Third, Moon: Moonshadow elves have this mantra that death isn't an ending, death is nothing to be feared (at least for themselves). Life and death are both sacred. That doesn't mean it doesn't hurt when it happens to those they care for. Lujanne is a bit of a trickster, who likes to play with people's senses.
As Lujanne describes, most think appearances are deceiving and reality is truth. The truth is all there is of reality is the appearance. This must mean that reality is what you make of it. We see only parts of the moon, but that doesn't mean it's not there, we just believe it's not. We believe the moon sheds light, but it's just reflecting the sun. We believe those who die are gone, but they merely enter another plane of existence. We believe we are eating food, it's just grubs. Reality is what we make of it; we see what we wish to see, others perceive what we wish them to perceive. Truth and lies, it's mainly based on the perception.
First off, Sun: Sunfire elves live in a grand capital, heavy with knowledge, healing, and justice. They have brilliant scholars, amazing healing magic, plus strong and capable warriors. They have a rich history and culture. They hold a lot of reverence towards the sun. Their funeral rites are to guide souls to it's embrace, "returning them to the sun." Karim shouts at the sun, "what would you have me do? Give me a sign!" when he is baking under it. He claims lack of hope is a setting sun. So it seems the sun is like their God. They at least hold great reverence towards it. They also have two forms, fire form and light form, destructive powers vs creative powers.
What can we gather from this? It seems that without the sun there is no life, no hope. With the sun comes energy to live, it can also very easily destroy. Fire is like life itself, you have to feed it, and give it air. The sun and fire can both be snuffed out, much like life. The sun is also always constant, even when there is clouds, even at night with the moon. The sun never leaves, it exists to give energy and strength to everything that lives, that persists in the plants and every living thing. The sun is the strength and vitality of life. The sun Arcanum is much like, "with the rising sun comes a new day." The sun is hope, and the strength to keep on living. The sun Arcanum is understanding that inner strength.
How about Earth?: Earthblood elves tend to live amongst the wilds. Warlon likes dominating dragons, N'than is a more timid elf boy, Terry has a great relationship with plants and a super understanding nature towards otherness. According to Rayla the drakeriders guard the drakewood from trespassers. They seem to have a strong sense of community...towards themselves, but I don't think it has to be limited to that. Terry did not fit into that community, and N'than didn't either; probably a strained sense of community. The difference between Warlon and those two is that those two are much nicer. Warlon demonstrates social order community, following tribal traditions, while Terry and N'than demonstrate community in generosity and kindness.
Terry has a great relationship with plants, and N'than may know his gemstones and lava, Ezran can speak with animals (which can be apart of the earth arcanum), and Rex igneous is a master of stone. From these we can gather what the earth arcanum's secret is.
N'than has a playful way of perceiving the world, especially with how he playfully introduces the zones of peril, also he thought Soren was cool for standing up to Warlon and defending the drake, he also is empathetic towards dragons. He's a friendly guy. Warlon, took pride in showing N'than the ropes of being a drake rider, as well as defending his home turf. Terry doesn't control plants, but has a good relationship with them, he asks for their help and he comes to their aid. He's also understanding towards Claudia, who just wants to save her father. He does draw the line at needless cruelty or violence, and can be torn up from necessary violence (killing someone). He's also a playful guy as well. As for Rex igneous, he understands the humans aren't really a threat and there is no need to decimate them, as well as everything that shines meets it's end.
This all seems to stem a few things. For one, empathy: Showing care for your fellow man so to speak, and even an understanding for your enemies. Rex igneous, while hostile to avizandum was friends with him before but thinks he's a fool because he can understand the human's situation. Also not helping with Aaravos at first, because it would endanger everyone, then comes to help when he understands what has befallen avizandum's family. What about Warlon? We didn't see much of him, but I could understand if he was brotherly with the other Drakeriders. N'than and Terry speak for themselves. Another thing is playfulness. Rex igneous loves surprises, rare desserts, and being given gifts in the past. Warlon has a lot of fun chasing down intruders and going after drakes. Again, Terry and N'than speak for themselves. Not to mention the earth golems were playing jenga, and proclaimed themselves guardians of the gate. Ezran also has a sweet tooth, and starts his council meetings and big events with desserts.
I should probably get to that Arcanum secret...okay. There are plants and animals, as well as rocks and stones. N'than, Terry and Ezran treat animals and plants with respect, Warlon not so much. So that's not a necessity. Earth is probably understanding the life within all things, plants and animals. Understanding that life is all around you, each having their own ways of living: food, water, reproduction, communication, knowledge, their own communities. You could be like Warlon and make them submit to you anyway, or you can treat them with respect. Yet this doesn't apply to rock and stone. Rex igneous points out that all things lose their luster over time. This applies to all of life, everything on the earth. All is susceptible to time and change, nothing on earth is immortal. Everything has a lifeline, everything has a life, and while you are living that life you might as well have some fun. "The early bird gets the worm," it means to seize the day while you have it. Diamonds and gems are things to cherish, to compare someone to an animal is to endear them, it's to give them love.
Now Star: All we have to go off is startouch elves and Stella. For startouch elves, all we have are the stories Aaravos told. Both Aaravos and Stella are playful. That's only one facet. Thinking of the other startouch elves, aaravos says humans are puny compared to them, as they are aware of their own greatness. Is arrogance a factor, aaravos saw potential in humans? What does arrogance have to do with the stars? Well, they say if you are star, you stand out. You are popular, you're eye catching. Stars definitely do shine, startouch aren't just shiny thy are powerful. Stars are also powerful, being able to suck people in, like Aaravos can draw people in. I don't think the Arcanum is just power.
Stella has the power is make pocket dimensions and portals, and startouch elves are masters of divination. That's all realms of space and time. That is very vast, while Stars are single points, so it's not vastness. What do stars do that nothing else does? My theory is that it's persistence, as startouch elves are immortal. Stars are long lived. They take a long time to be created, they live for thousands of years, and even after they die it'll be hundreds of years before you notice. It takes many elements to make a star, and it takes a long time to reach any goal, to achieve greatness. "Rome wasn't built in a day," so to speak. Patience is not a trait of the stars, so it's not waiting for greatness. Instead it's understanding that their power will persist, memory also persists, everything has an echo. Much like starlight takes hundreds of years to reach earth, anything that happens will be remembered, it take a while for anything to truly die.
That's my 2 cents on the Arcanums and my understanding of them.
Tldr: Sky=agency and freedom, Ocean=faith and trust, and mystery, moon=reality is what you make of it, sun=the strength to keep living, earth=everything has life,star=power/action and memory persist
