Sorry for the obscure title - not.
First off, thanks to Hail-Raise-Zhar for the idea and his support.
Without any further ado, here we go:
There are ways with which to defeat the ancient one while he is awakening and/or when he has already awakened without doing him harm . I have read the ancient scriptures, and through my perusal of the dread Uralte Schrecken and the soul-blasting Tractatus Logico-Philosophicus I have freed my mind from the blessed shield of ignorance which men mistake for healthy minds. Here is what I found:
1.) One could, in theory, wait until the ancient one has awakened and use Silas Marsh's personal story to sacrifice oneself to gain a sixth seal during final combat, wasting away to the madness of the sea so that humanity can eke out a few more centuries...decades...or however long it still has before the final oblivion.
2.) Similarly, as one is never removed from the location one is in, one could theoretically sacrifice the last few few clue tokens to complete the Mission "For the Greater Good", winning the game, again, through devourment of the self!
3.) If in the correct location, "Walking the Ley Lines" could similarly prevent the dark one from manifesting, if the requisite number of gate trophies are present when one performs the final sacrifice.
4.) One could prevent Eihort's entry into our realm if the final brood token that slays you both awakens hima nd seals the sixth gate. A noble, yet futile gesture.
5.) If Mandy Thompson were to gain the fifth clue token needed for her to activate her personal story card while the sixth Deep One Rising Token is placed, she can also perform the sixth seal required to seale ye ancient abomination from the land of the living.
6.) Anyone during the Arkham Encounters phase could, when the final gate, the last corruption or a monster/gate that cannot be drawn is there, read the De Vermiis Mysteriis and close the last open gate, if the gate that just appeared would satisfy that winning condition.*
7.) If Akachi Onyele, great descendant of a most dreadful witch, should be present when an encounter opens the final gate, causes the last corruption or calls upon a monster/gate that cannot be drawn, she could use the passages in the De Vermiis Mysteriis to seal the final gate necessary for denying the things from the outer dark.*
*If Eihort be the Ancient One, then one can also perform these victories through casting a Bind Monster card that slays a cultist, then subsequently exploding due to the Brood Marker gained; similarly, slaying a cultist of Yig thusly can be a situation where one uses the De Vermiis in this manner. Also, if Rhan-Tegoth be the Ancient One and a Cultist is drawn from the cup that awakens him, one may performt his feat. Or if Glaaki is awakened through the fifth of her Servants appearing during the encounters phase. Or in general if the Terror Level were to rise too high during this phase, awakening the ancient one. Or Yig awakening due to an unfortunate stumble into Lost in Time and Space. I.e., if the Ancient One somehow awakens during the Arkham Encounters Phase, one may use the De Vermiis to perform those two feats.
However, ye best chances lie not in saving Humanity. If one really wishes to succeed, one needs to call upon that dread power from beyond, embracing it with all one's heart and soul!
8.) One could theoretically Awaken Glaaki with the final sacrifice required by Joining the Winning Team - one gets to usher in one's master's arrival to the pitiful screams of one's former, foolish allies!
9.) However, even other ancients can be assuaded to not devour thee if you present them with the correct sacrifice. When already Lost in Time and Space, and ye Master doth appear, he will try to DEVOUR you in his ravenous hunger. Yet, this fate can be averted by presenting him with ye MESENGER, allowing ye to live long enough to perform the finale sacrifice!
10.) Especially in ye case of averting the wrath of the great serpent...IÄH YIG! AYEE, AYEE...then mayest ye awaken him by becoming LOST IN TIME AND SPACE, then presenting him with thy MESSENGER to prevent him from destroying you with his endless wrathhhhh...giving you time to shed your skin and join his blessed brood through the final sacrifice! MWaah...ahhaaahahaaaa...AHAAHAHAHAAAAA!!!!
But....are these all the ways in which one may do these things...I must be prepared...the hour draws near....I urge ye, help this faithful servant!!!
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(Disclaimer: The OP wished for us to make the following statements, but was...otherwise indisposed to make them of his own accord:
- Some of these rule examples involve three lesser known facts: When the ancient one awakens, you are never removed from your current location/other world/etc.. Also, When two things happen at once, one is allowed to choose the order of events that take place. Finally, one immediatley wins when six seals are on the table, regardless of other things happening at the moment. So be careful before dismissing these examples!
- The OP is aware that various Doom Token removal abilities can theoretically destroy the ancient one while awakening. These have been left out on purpose.
- The OP wishes for you to come up with more examples that could produce a similar effect - i.e., winning the game either at the same time as the ancient one awakens OR when he is already awake. Epic Battle cards that cause the investigators to win, on their own, DO NOT COUNT!
- The OP may need some recovery time before responding to posts. He appologizes for the inconvenience.
- The OP also wishes to ask the user by the name of "Dam" whether this answers his previous question about the item mentioned in the title of this post.
That is all. Good day, dear reader.)