Warning. If you haven't played Forsaken Lore, spoilers are ahead...

So I've played against Yig four times so far, each time he awakens. I'm having a problem with the line that when an investigator is devoured or defeated they are not eliminated. So what are they? I get that it causes the doom to drop, which means an Eldritch token is taken off of Yig. But what happens to the investigator? Reduced to zero strength or sanity and delayed? Dark Pacts no longer have an effect? Nothing?

Yig has always awakened when I'm not even close to solving three mysteries so every game has ended in defeat. But until I understand this no win I may have will seem clean.

Yig seems somewhat nerfed if defeat doesn't eliminate an investigator once Yig awakes. Expescially since his final mystery is combat oriented. But in AH and ES Yig is the easy GOO. So maybe that is what they were going for here.

I think it means that while you normally can't replace your investigaror after the Old One awakens, with Yig, if your investigator dies or goes insane you can choose another one to replace him/her.

Yes. In game if an investigator gets runs out of health or sanity, the player may choose a new investigator from the unused pile. If most Ancient Ones are awake, the player is eliminated instead. He sits the rest of the game out. Yig is the only AO where this isn't the case (except for Azathoth, where everyone just loses the game).

Notably Yig has a very short Doom track compared to the others at only 10 Doom. The tradeoff with Yig is he is easier to beat by Final Mystery, but you are much more likely to have to do so.

Ah. Investigators the players, not the characters. I knew the answer was going to be stupidly simple. Thanks