Marathon Horror is a variant of Arkham Horror in which many Ancient Ones are threatening the world all in quick succession.

Marathon Horror uses the “weak seals” variant (courtesy of Dail):
If you would place an elder sign token on the board, instead place 3. If a gate tries to open at a sealed location, instead remove an elder sign token. If a gate burst occurs at a sealed location, remove 3 tokens. If there is still at least one sign on the location, the gate burst is prevented. These tokens don’t individually count as elder signs; you need 5 sealed locations, not 5 elder sign tokens on the board, to win through seals.

When setting up the game, choose an Ancient One at random. Choose a Guardian (if desired) as normal. Choose a Herald at random. Finish setting up normally.

If the investigators manage to get 5 seals on the board, the Ancient One is not defeated. Instead, this is rewarded by a choice: Choose a new Guardian to help you (in addition to the current Guardian), or remove 5 doom tokens from the doom track. If the number of seals falls below 5 and comes back up, you do not get the reward again.

If the investigators manage to get a closed gates victory, the current Ancient One is defeated. Discard it and all gate trophies, and as a reward, the investigators may either discard one of the current Heralds as well, or choose a new Guardian to help (in addition to the current Guardian).

If the Ancient One awakens, one of the Guardians flees. The investigators must choose a Guardian to discard. If the Ancient One is defeated in combat, the players may choose to close a Gate as a reward. All Heralds remain in play to help the next Ancient One.

If the Ancient One is defeated (through a closed gates victory or through combat), the investigators get one free turn. At the end of that turn, before the Mythos Phase, choose a new Ancient One and a new Herald, both at random.

When choosing a new Guardian to help, you may choose Guardians that have previously fled. When choosing a new Herald at random, do not include defeated Heralds. If there are no Heralds left, the new Ancient One instead begins with a doom token on its doom track for each time this has happened. When choosing a new Ancient One, do not include defeated Ancient Ones. If there are no Ancient Ones left, the investigators win!

Yenreb said:

Hmmm, that sounds somewhat easy, as you can stock up on equipment and clues in between games, errr, ancient ones.

Avi_dreader said:

Yes, but victory by seals is removed for a one-shot reward, which makes actually defeating each GOO (16 currently) significantly trickier. Even Final Battle isn't as easy, as the investigators will be heavily drained after each one. Also, it appears as though the Terror level will stay up, so stores will be closed probably within the first half of the Ancients. And don't forget the acquisition of extra heralds, which means many difficult challanges can overlap.

I think I may actually try this over spring break (Next week, woo), since I'll have loads of time. Of course, I'll make sure Azathoth is that last GOO, both to make it thematic and to make him tough (Terror at 10 and whatnot...).

The Message said:

Hmm... I'll grant that terror can be an issue (unless you have Charlie). Still.... There's no reason to think you won't be able to buy out all the decks before terror becomes a significant problem— if you make that a strategic aim. ::Shrug:: clear out the common item store and always keep the Directors Diaries at hand, and you should be able to keep the terror down. I still think it's easily breakable as long as you don't start off against someone like Yibb Tsill or Y'golonac. And I didn't even bring up the problem of hording skills. Btw, what happens when you fight Shudde Mell btw, are those buildings permanently destroyed? Hrm... Same with Blights. Do they stick around between games?

Note that the Terror Level can go above 10, as implied by the wording on Glaaki. It's just that the most common method of terror level increase (the outskirts) is removed at 10. This is relevant if The King in Yellow becomes a Herald after the terror level has already reached 10. There are still a few ways for the terror level to increase, so its effect may be relevant.

If you're considering this variant, be sure to include any custom heralds, guardians, and GOOs that you think would be interesting. I've posted two GOOs and a Guardian/Herald pair in their respective threads, if you want to consider them.

As for making Azathoth the last GOO, that's not a bad idea. In this format, the only way to defeat him is a closed gates victory, so good luck! Especially with all the heralds lurking around by the time you get to the end.

Servitors

If you want to use servitors, choose 3 at random at the start of the game in the place of a starting herald. (You'll still add heralds as normal later on.) To deal with the problem of a permanent seal making things too easy, include "Awaken all Servitors" as a possible "herald" when adding a herald with a new Ancient One. (Don't include it if there aren't any defeated Servitors at the time you're adding a new herald.) When "Awaken all Servitors" is chosen, return all defeated Servitors' elder sign tokens back to their doom token sides, and remove the permanent seal from their location. "Awaken all Servitors" then returns to the "deck" of possible heralds in the future (ie. you can't choose it as the herald you want to remove when you get a closed gates victory).

Hrm... Also, in terms of breaking the game... If you can buy out the unique item shop, you can get access to Eldritch Tomes every turn (and have control over the doom track). In the meanwhile you can raise money to buy out the common item shop (so you can have continual access to the directors diaries). Once you accomplish those two things, it's basically game over for the AOs. Iow, this variant will only be challenging if you screw up or deliberately don't strategize to take advantage of it ;')

Buildings destroyed by Shudde Mell stay destroyed, and Blights brought in by The King in Yellow stay in effect even if you discard The King in Yellow as a herald.

Similarly, any monsters stay on the board when you defeat an Ancient One, and any gates that are open when the Ancient One awakens stay open (except for the one you choose to close as a reward for defeating the Ancient One in combat).

It just occured to me that there might only be one gate open when the Ancient One awakens. In this case, closing that gate does not defeat the next Ancient One before it gets chosen, but you do get the benefit of adding a Guardian or discarding a Herald (assuming you have enough gate trophies for a closed gates victory -- remember, this causes you to discard all of your gate trophies).

Yenreb said:

You only can get a gate closing victory if you have trophies equal to the number of players (and I think the variant says you need to discard your trophies between AOs— that's probably why).

Grr. You quoted me before I edited my post. xP

And, yes, that's why you have to discard your gate trophies when you get a closed gate victory. Note that you do not discard your gate trophies if you defeated the Ancient One in combat -- but neither do you get to claim the free closed gate as a trophy, and you can't seal it either.

I made a mockup of a card to represent "Awaken all Servitors":

Yes, it has the default Herald picture. Deal with it.

I just realized I never specified this:

If an investigator is devoured during combat with an Ancient One, but the investigators defeat the Ancient One anyway, that player starts a new investigator, just like when an investigator is devoured outside of final combat.

Obviously, if the players lose in final combat, nobody starts a new investigator, since they just lost the game.

Now, it could be the fact that it's 2 that's clouding my thoughts, but what are Servitors? From what I've gathered, it sounds like a cross between a GOO and a herald, but I don't think I've ever heard that term before in AH.

On an unrelated note concerning devourings, I normally don't even allow redraws as there's only ever two of us (Playing multiples) and it makes them actually a penalty instead of a possible blessing. I may have to waive that for this version, however...

The Message said:

Servitors are custom content which predate Strange Eons (and maybe Heralds themselves), or so I have been told. There's a plugin somewhere that lets you make Servitors in SE, and the Plugin comes with an explanation of how they work. Essentially, they're uber-monsters that have to be defeated three times to actually kill them, and each of them has a benefit (for the Ancient One) if it's still alive when the Ancient One awakens. If you do defeat a Servitor all three times, you get a permanent seal on their location. If you don't want to use Servitors, don't worry about them; you don't need to use them for Marathon Horror. I just wanted to create rules that would allow people to use them if they wanted to.

I just realized that this variant breaks if the Corruption deck is run dry, because every GOO will thereafter immediately awaken upon being chosen! To handle this, if an Ancient One awakens due to an empty Corruption deck, remove that as an awakening condition for future Ancient Ones. Or, shuffle the discards of the Corruption deck (keeping Green and Red separate) after defeating an Ancient One which awoke due to an empty Corruption deck.

A number of GOOs and Heralds (particularly custom stuff) reference the terror level, which may already be 10 or higher. I said in a previous post that the terror level can go above 10, as implied by Glaaki. But the rules elsewhere say that if the terror level would increase above 10, you instead add a doom token. So let’s reach a happy medium: The terror level itself cannot be greater than 10, but it can “rise” in the sense of triggering effects that care about the terror level increasing (such as the King in Yellow herald). Each time this happens, you also add a doom token. (So, if the KiY herald was in play and the terror level is at 10 and tries to rise, you'll add a doom token, and then either add another doom token or put a Blight into play.)

Special Notes Regarding Ancient Ones

Abhoth:
When Abhoth becomes the GOO, return all Cultists from the monster cup to the box. Any Cultists on the board remain, as do any Cultist trophies investigators may be holding. When a Cultist trophy is spent or a Cultist on the board would be returned to the cup, it is returned to the box instead.
When Abhoth is defeated, put the removed Cultists back in the cup.
When Abhoth is defeated, any of his Spawn monsters on the board are returned to the box.

Cthulhu:
Any damage the investigators take during final battle with Cthulhu is permanent. But note that defeating Cthulhu does restore the maximum Sanity and Stamina loss from his “stirs in his slumber” effect.

Eihort:
Unless you’re using a custom Herald that uses brood tokens as well, there’s no reason to keep your brood tokens after you’ve defeated Eihort.

Glaaki:
When Glaaki is defeated, any of his Spawn monsters on the board are returned to the box.

Nyarlathotep:
When Nyarlathotep is defeated, return any Mask monsters from the cup or board to the box. Any Mask monsters that have been claimed as trophies are kept. When they do get spent, return them to the box rather than the cup.

Shudde M’ell:
Rubble tokens from Shudde M’ell remain in effect after defeating him. Killing a monster doesn’t repair the buildings the monster destroyed.

Special Notes Regarding Heralds

Ghroth:
Ghroth’s “The End Is Near” ability applies to the Ancient One he joins when he is initially chosen as well as every future Ancient One chosen while Ghroth is still a Herald.

Black Goat of the Woods:
When this becomes a Herald, remove all hex monsters from the cup for the separate hex cup. When this is defeated, put the hex monsters from the hex cup back in the normal monster cup.

The King in Yellow:
The Yellow Sign ability triggers each time the Terror Level increases. It also triggers if the Terror Level is already at its cap but an effect tries to increase the Terror Level.

Tulzcha:
If Tulzcha is chosen as the new Herald and Abhoth is chosen as the new Ancient One, put Tulzcha’s extra Cultist on the first gate that opens before you remove all the Cultists from the cup.
The Cultists’ ability which removes an elder sign token instead removes 3 when you’re using the weak seals variant (as Marathon Horror does).

The Dark Pharaoh:
When this is chosen as the Herald, add the Dark Pharaoh monster to the cup. When this is defeated, return the Dark Pharaoh monster to the box.

The Dunwich Horror:
When this is chosen as the Herald, put a token on the Dunwich Horror track. If the Terror Track is high enough, add additional tokens as appropriate.

Special Notes Regarding Guardians:

Bast:
Bast tokens a player is holding when Bast flees are lost. The flavor here is that Bast is continually protecting the player.

Nodens:
Blessing of Nodens cards a player is holding when Nodens flees are retained. The flavor here is that Nodens granted a blessing at the time the player got the Blessing card. Nodens does not need to continue to be present for his blessing to retain its effect.

Special Notes Regarding Custom Ancient Ones:
Here I only have looked at the latest versions of Ancient Ones in the Custom Ancient Ones thread on this forum. No other custom Ancient Ones are evaluated here. If a card from that thread is not listed, it does not need any special rulings (unless that card was posted after I made this list, of course).

Borkrug:
The Start of Battle ability only counts investigators devoured since the point when Borkrug became the Ancient One. Devourings before then are not counted (because you've probably forgotten by then).

Kefka:
Ancient Ones are added during the Mythos Phase of the free turn, before drawing a Mythos card. So treat the Mythos card drawn right after picking Kefka as the “first Mythos card.”

Hastur:
If you use this, don’t use the official Hastur in the same game of Marathon Horror.

Special Notes Regarding Custom Heralds:
See the side note above. The same applies for these custom heralds.

Fah’ic:
The “when setting up the game” effect is triggered when Fah’ic is chosen as a Herald. Defeating Fah’ic removes his Impacts from play as well.

Master Therion:
Locations closed by this herald are reopened when he is defeated. If the Deputy cards are returned to the box, they do NOT come back.

The Sky Tore Open:
When this is chosen as a herald, if the Terror Level is between 1 and 5, the cap is moved from 10 to 5. Any effects of this herald that should have already triggered do so now.
If the Terror Level is between 6 and 10, the cap is put wherever the current Terror Level is. All of this herald’s effects should have already triggered; they do so now.
The ruling I made for the Terror Level trying to increase but failing continues to apply even when the cap is lower than 10.
When this is defeated as a herald, the Terror Level cap moves back to 10. Locations closed by the Terror Level never reopen, but the Maniac threshold is returned to 6 and the monster limit on the Outskirts is restored (unless the Terror Level is already 10).

Nyarlathotep:
If you’re using this as a potential herald, do not include Nyarl as a possible GOO.
When this becomes the herald, return all Elder Sign cards from the Unique Item deck to the box. They are not returned to the deck when Nyarl is defeated. Any Elder Signs currently held by investigators are retained.
The “My Name?” ability triggers on the Mythos Phase following his selection (so the next turn). But it’s unlikely that any investigator will be able to use it.
“Let’s See If You Can Handle This” triggers as appropriate if the Terror Level is already at or past 3, 6, or 9.
“A False Summoning!” replaces the current Ancient One with one at random among those that have not been used yet. If the current Ancient One is the last one, the ability does nothing and you fight that Ancient One as normal.
“I Will Not Let It End Like This!” triggers as normal. Note that you only get to close a gate for defeating the actual Ancient One; defeating Nyarlathotep this way does not let you close a second gate (nor does it scare away another Guardian). But defeating him this way defeats the herald too.
If you defeat Nyarl the herald using a closed gates victory, return Nyarl the AO to the pot of future GOOs.

Special Notes Regarding Custom Guardians:
See the side note above. The same applies for the custom Guardians.

Xuo:
When Xuo flees, remove any Xuo’s Influence cards from play. If you choose Xuo as the Guardian to flee, you cannot discard the Influence cards to remove doom tokens.

Samuel Colt:
When Colt flees, his Bullet tokens and Arsenal cards are retained. They were gifts from Colt; he doesn’t take them back when he runs away. But note that the Bullet tokens are useless unless/until Colt rejoins you, since their only use is in the “Deadly Bullets” ability, which is lost when Colt leaves.

Richard Upton Pickman:
If Pickman is lost as a Guardian, any Ghoul Allies are lost as well and return to the cup. (At least they don't turn against you right away.)

Hestia:
When Hestia becomes a Guardian, set aside a pool of 2 tokens for the “Family” ability as normal. Set any “Food” items from the Common Item deck in a “food pool” as well, as normal for the “Meals” ability.
When Hestia is lost as a Guardian, the “Family” pool of tokens is lost. (If Hestia later comes back, the pool is reset to 2.)
When Hestia is lost as a Guardian, shuffle the Food pool back into the Common Item deck.

Ascepius:
When Ascepius is lost as a Guardian, any Herbs cards held by investigators are retained.

Mad Spirit of Abdul Alhazred:
When this is lost as a Guardian, investigators’ maximum Sanity is restored by 1.

Yenreb said:

That actually sounds really interesting, I'll have to check those out.