Today I played for the first time against Abhoth - yeah, I took my time. Anyways, each Child of Abhoth curses the investigator who completes its monster task as a part of the task itself. Now, the curse is removed after successfully completing an adventure card. Does it mean that if I succeed at an adventure with the Child of Abhoth on it (preferrably save it for the end, to avoid being cursed for subsequent tasks), the curse just goes away?

I mean, the penalty seems to be no penalty at all (of course, there may be an adventure with an arrow and the monster task is the first one, but let's ignore such situations for a moment). That makes the monsters more of a nuisance, than a threat. Or have I understood something wrong rulewise?

You keep the cursed die in your pool even if you resolve the adventure where you are cursed. You can cross-check this in the rules, pag. 3, second paragraph of the "Cursed and Blessed mid-turn" subsection, which reads (emphasys mine):

If an investigator becomes cursed in the middle of resolving an adventure, he does not discard his Cursed card after successfully resolving that adventure. He must successfully resolve another adventure in order to discard the Cursed card.

Ah, I see. That's what I have overlooked. Thank you.

Glad I helped

For this reason alone, Abhoth is my #1 nemesis...I can't tell you how often my Investigators became Cursed in our last game.

Aye, he's a toughie. Good strategy: stockpile items allowing you to discard adventures and monsters (no spawn monsters here, fortunately) and focus on the free adventures. Often 4 days are enough to kill the game, so, you just need one item allowing you to discard one of those. Otherwise, leave them alone for a while, gain trophies to buy blessings and sent Blessed investigators killing the dudes.

That's exactly the strategy I'm going to try out. The game is set up and I hear that a storm is coming here. Let's rock and roll!

Good luck with that my friend, and let us know

After two games, my score is 1:1. In the first one, Abhoth didn't know what hit him. I admit that it was more about luck, because I didn't find many hard adventures or locked dice.

In the second game, Slithering Shadows adventure (doom +3 if a monster is in play) coming right before midnight caused my demise. It accelerated doom to 7, then Kate Winthrop died in an epic fumble (I swear the dice gods did this on purpose) and the final mythos card added the final doom token. Final fight was more of a farce, Abhoth has enjoyed his snack.

Yeah that was the one thing we kind of had to concede during playtesting: a curse die task is essentially countered by the rule that passing an adventure discards the curse. Rather than to re-tool the curse mechanic, the simplest solution was just to add the clause the Julia quoted.