A lore summary of the darkin(with some speculation near the end)
Who are the Darkin
Src: https://universe.leagueoflegends.com/en_US/story/the-legend-of-the-darkin/ The Darkin are former Shuriman ascended (see: Nasus/Renekton/Azir for more detailed information on these, but basically gods). When opposing rebel forces in Icathia released the void they fought at the front line, causing corruption spread through the Darkin, but stopping the void in its place.
After shurima fell, the ascended that fought at the front slowly became more corrupted by what they saw at the void(A prolonged exposure to the void makes you insane, but stronger characters of mind and soul remain sane it for a longer time) and started the Darkin wars. The name Darkin was given to them by the people who lived on the lands devastated by these wars.
The Darkin were considered unstoppable until mages figured out that you could trap them in their weapon. According to certain voice lines of Aatrox, the one might have taught them how to do this is Zoe. In the voice lines Aatrox uses against Zoe he always screams that she is a traitor, but in both his lore and his vocal lines it is never actually 100 percent confirmed if she was the one that shared the magic.
There are now 4 (confirmed) existing Darkin left. Aatrox, Varus, Rhaast and an unnamed one that is the sister of Varus. Some others might be alive, but most were slain by one of the Darkin in the twilight of the gods story. (https://universe.leagueoflegends.com/en_US/story/twilight-of-the-gods/)
The Darkin that are still left in their weapon have the power to corrupt any person who holds them into their own new body. The weaker the body, the easier the corruption. If the body of the owner is too strong, the owner can subjugate the Darkin(see: Kayn) or block the full body power of the Darkin(varus being blocked by 2 people), but most mortals are just directly absorbed(see: Aatrox). The term term Darkin means the fallen.
What they were.
This part is mostly speculation, but I think you can even trace back what kind of god they were before they became part of the void. They were sealed in the weapons they were holding so the weapons give us an idea of who they were.
Rhaast: Rhaast was probably an ascended of farming. He has the scythe, which is a tool for farming. He was also a formidable fighter as Rhaast as he is shown to get respect from other Darkin in the above-mentioned twilight of the god event.
Aatrox: Aatrox is either a Ascended of war or justice. Certain lines seem to show an inherent sign of justice and many judgment gods wield a sword as well. He also has wings, something that we often associate with justice.
Varus: Archer or hunter Ascended. My expertise of bows doesn’t go far enough to tell if it is a hunter bow or a combat bow.
Summary of individual lore. **Aatrox: ** Aatrox is currently kinda complicated. He had a really good lore before the rework and he still does now. They were good in different ways, the old lore set him up as somebody that chose wars and helped a side win in order to push a world that has longer lasting wars.
He had fought in a battle of magelords versus normal humans and sided with the humans(possibly the origin of Demacia, who hate mages(not confirmed)). He also made Tryndamere into the person he now is which made the alliance of Avarosan(tribe of Ashe) way stronger then it is now(this is still canon).
Overall he seemed like he was preparing the world for something(possibly another war with the void).
In the current lore, he is a more complex character, with a more tragic story and a more reasonable reason to fight. He feels betrayed by everyone and is slowly losing his humanity staring into the void. He is the strongest presence for a host to fight against, as he can take over a host in a single breath. He is also interesting as a character as he longs to be whole again or to cease existing, yet being unable to do either.
On the other hand, he does no longer play a big role in the bigger picture lore of League. His lore with Tryndamere is kept intact, but some of the more cunning aspects of him have been removed.
Varus: Varus new lore is an adaptation of his old lore. In the old lore, he wanted revenge against noxus and threw himself into the pit where Varus is contained in order to become strong enough to defeat noxus. He does get corrupted but keeps partial control.
In the new lore, one of two lovers jumps into with the other to become Varus absorbs them both and sets out to murder Noxians and free his sister. He is in constant inner combat against his 2 hosts that prevent him from achieving his goals. In this lore, it gets confirmed that the sister of Varus is possibly free again.
Rhaast: Rhaast always only partly corrupted the souls of the people that picked him up, waiting for a worthy host. Kayn is worthy and he wants to use Kayns body to continue spreading destruction as a god. Of all the Darkins, Rhaast is probably the most corrupted in comparison to his old form, having no other goal than fighting.
https://universe.leagueoflegends.com/en_GB/story/champion/kayn/
In lore, who is the strongest.
They are probably around the same strength. Aatrox is clearly a war god and can absorb mortals in a single breath. He also has the most warlike weapon and wings. He is however very careless and loses a lot of bodies due to his uncontrolled bloodlust. https://universe.leagueoflegends.com/en_GB/story/aatrox-color-story/
Rhaast has the strongest most useful host and becomes the strongest would he absorb Kayn(gaining a lot of op powers), but he is still struggling currently.
Varus is strong because he has a double host to draw power from, but weak because the host can also block a lot of his actions because of it.
What I hope Varus sister will be
I kinda hope that they make Varus sister a symbiotic Darkin that works with her host to reach a common goal. Most current Darkin have a goal to reach full body anatomy, so it would be interesting to see a Darkin that has learned to live with her curse. It would also be cool to have a Varus like being that is in harmony with both her sides.
##In closing I really like the Darkin and hope that they will continue to update both their lore and part in the universe. I really hope you enjoyed reading some of my weird theories and lore explanations.
and
can count as Darkin too btw.