Anyway, there are other possibilities left, some of which have been exposed, some merely mentioned, and some new ones... Let's see what they are.
(FYI, despite being known for my twisted plots, I'm leaning toward the simple Gareth = Benekander, but I hope you find some of these ideas interesting and use whichever you want IYC.)
So there is:
1. Gareth = Benekander.
2. Gareth = Rad.
3. Gareth = Loki/Bozdogan.
4. Gareth = Thanatos or Hel (or Gareth = another Entropic).
5. Gareth = a new Initiate.
6. Gareth = an Old One.
7. Gareth = an Immortal returned from the Vortex.
8. anything else you wish (I'm sure you'll remind them to me).