Recently playing Kingsport, one of the investigators was Charlie Kane, who has the ability to gain Allies who have been returned to the box.  During play, the mythos card for the Southside Strangler came up, which has an ongoing effect of randomly returning an Allie to the box, which Charlie can gain as an Ally.  The Elder one for this game was Atlach-Nacha, which for his attack  forces the group to choose an investigator or Ally in play.  If an Ally is chosen, it is returned to the box, which allows Kane to gain it as an Ally. So we had an infinite amount of turns to kill Atlach-Nacha. Is there any clarification?

The wording is pretty unclear, but Charlie's ability doesn't automatically give him an Ally whenever it's sent to the box; all it means is that he can gain (through normal Ally-gaining means) allies that would otherwise be unavailable.

wobots said:

I'm pretty sure the intent of Kane is not that he can gain allies returned to the box at will, but that when he has the opportunity to gain an ally that could not be gained if it had returned to the box, he could still gain the ally.

 The above two posters are correct. There's a reason Charlie Kane is the weakest investigator (by percent wins) rather than the strongest. 

I will say this ~ Charlie is the man to have on your side against Hastur!

 Now that you mention that.  I'm tempted to throw Charlie into a game against Hastur along with say someone like Patrice (who would be game breakingly hilarious).  Get money, get clue tokens, tool up.  Let Hastur spawn and savagely beat him!

That reminds me of how many weird easy-hard synergies there are out there that I really haven't explored.  For example, I bet you could make an interesting game out of Charlie and Patrice vs. New Hastur, Dagon, and Hydra.  Or Rhan and the Lurker.