If Ahri is Vastayan, this may be why she is stealing souls.
So in the text introducing Vastayan, Mr. Santangelo stumbles across Ahri. While the only details in this encounter demonstrate that he was thinking with the wrong head, it brings the startling idea that her lore is being retconned. Now I know that Ahri's lore is very dear to her player base, but I feel like what Riot is attempting to do is integrate the legend of the Gumiho into the league universe in a less "copy and paste" manner.
Here's what we know:
Ahri was spotted in the same area where Santangelo saw the other Vastayans. Now this doesn't confirm that she is one, but it would make a lot of sense if she was, given her physical semi-human characteristics. Surely this would rile up some Ahri mains, since her old lore is pretty unique. However it is also vague and detached. Ahri never interacts with anyone from the league universe and as we know, there are a LOT of people/things/concepts to interact with. So let's focus on what makes Ahri, Ahri:
*She has fox tails and ears harkening to her heritage as a pure fox at one point
*She has the ability to seduce men, (and by the look of her fanbase, unintentionally too ;) )
*She steals people "life essence" to fuel her transformation into a full human
*She has a conscience, and understands what her actions do, so she is searching for a better way.
Now if Ahri is Vastayan, what incentive does she have to steal life essence from people? Why does she have the powers she does in the game? The answer is simple and it is given to us immediately following the meeting. The pig-man Shai explains that if a Vastayan's blood is too diluted, they lose the ability to transform between shapes. Now given the method by which Vastayan are born, (which could be magical OR physical), there is no doubt that internal magic is what powers the transformation. What is lost isn't the ability to transform between shapes-that is hereditary and unchanging- what is lacking is the internal magic necessary in doing it.
Due to this, Ahri may have been born as a full fox, retaining that aspect of her lore. Initially unbeknownst to her or not, she possessed an ability to absorb a being's magical power/life energy. In typical humans, this may be their life energy, and in mages, their mana/magic power. As she gains more and more power, Ahri would slowly shed more and more of her fox body until the transformation was complete. However, her joy would come at a harsh price, as it seems that magic users are scarce in this sector of Ionia, and magic permeates the air and nature rather than the body, Ahri must kill to get the necessary power. This is why Shai warned Santangelo about approaching her, he has probably witnessed a similar fate.
As Ahri becomes more an more human, she is hesitant to kill, which is why, perhaps, she did not kill Santangelo when she noticed his presence (which she must have because she left the area). In essence-lol pun- Ahri is the same soul stealing fox lady we know and in my case....tolerate, in yours probably love. Her background is simply has the potential to intertwine with other champions now. This has been Riot's goal in many lore reworks, and they have done a fantastic job of linking champions together.
What are your thoughts?
EDIT: After Spareatick pointed this out to me I realized I had a copy of the story with a typo. The actual story has the diluted Vastayans with the ability to transform. Since this is the case, I can make a conjecture that Ahri is one of the older, purer Vastayans, who suffer from the inablity to use internal magic, and it is instead the fusion of human and shapeshifter abilties that allow the diluted vastayans to control their transformation. In Ahri's case, she is simply unable to transform on her own, and, after watching the new blood transform, longs to be included with humans, and so pursues the transformation by using the life essence of others.