[Theory] Tahm Kench, the River Darkin

I have always been a fan of the Lore side of League of Legends. If you are interested and haven't already I highly suggest reading dialMARK4action's series "Facts, Myths, and Theories". My current theory which according to the title is as follows. Tahm Kench is one of the five remaining Darkin. I haven't followed up on this theory heavily quite yet, but wanted to begin at least writing down some notes or reasoning why this seems viable. Firstly we know little about the darkin beyond there are five, aatrox is one of them, he has little to no contact with them (this tidbit was released in a Q&A discussed in one of the FM&T discussions).

Current Theory: The Darkin are the demons that embody or are avatars for human vice. For some reason, currently unkown, there are only five left. Two of which are Aatrox, and Tahm Kench.

Reasons why:

1. Aatrox and Tahm are listed as Friends on Tahm's champion page. While in many cases when taunting an enemy champion Tahm will use 'boy' or 'girl' to address someone. Aatrox is the only recipient of the term 'brother'. Specifically, (Enemy Aatrox) "Brother, you're as cultured as a crematorium selling barbecue."
2. Both unilaterally represent one aspect to an extreme, namely one of the seven deadly sins. Aatrox being wrath, and Tahm Kench gluttony. Aatrox commonly refers to "what lurks in the hearts of men"; his presence, as stated in lore, brings rage and bloodthirst to those around him. Tahm is clearly appetite focused (puns) and he shows an appetite not just of a physical nature. He seeks out those with large appetites for vice, assists them to feed off of the subsequent despair upon his return.
3. "Instead you're the fool, the fool who let me in.". Both show the ability to influence the mental states of others. Aatrox's notable one is his 'greatest creation' Tryndamere.
4. Looks don't matter. Aatrox's ultimate show that his appearance is at least mildly malleable and in Tahm Kench's Q&A it was said that, "His appearance and name changes from culture to culture, person to person. His current form is linked with Bilgewater."

This is somewhat of a rough outline and I'd like to see others thoughts on it.