If you click on the quest name (or here: https://grandorder.gamepress.gg/c/quests/olga-marie-quest-2-2-3 ), you can find a more detailed description of the mechanics of the quest. This quest has quite a few details, so this page sort of works as a stand-in guide.

TL;DR, certain enemies in the battle give you "Presidential Badges", which you can spend on the special Mystic Code skills. These are kept between waves, so one of the goals would be to try to kill as many enemies per wave as possible to get as many Presidential Badges, and to stock them up for the final 10th wave. Once you're up against the final boss, you can spend them all to buff up the damage dealer to increase your damage output.

Hey there! Are we getting a guide on this quest? It's pretty hard. In particular, I'm not sure how the mechanics of it work. There are 10 parts and each part has several waves. But each part only allows you a set number of turns to clear the part. But even if you don't clear the part in time, it still allows you to move on to the next part. What's that about?

Thank you for all your hard work. I think I speak for many when I say that this game would not be the same without you.

every guide before LB7 doesnt work

I've reported the error to the server manager, they are currently looking into it! Hopefully it will be fixed soon.

Step 62, 17-4 miniboss, the back Avenger must be defeated before the front Avenger loses her first bar or she'll respawn after defeating the Berzerker that replaces her illusion. This can be worked out from the full battle notes but a warning on this page might be a good idea.

Thanks a ton, I've added a cautionary note to the miniboss description section! Should be live shortly.

#442 isn't appearing here :( I think it's only accessible from the home page link

For Step 30 (11-2), it isn't actually necessary to break the Avenger. I got her down to about 6k hp and wiped her minions on the first turn, and that ended the fight. She said something about her hordes being endless, so I think wiping out the minions is an alternate clear condition.

Oh thanks, looks like there are indeed two triggers: so long as she is alone on the field or if her first HP bar is broken. Updated! Should be live in a few minutes.

My friend said the easiest way to keep the Myth is to make Sita an alternate costume for Rama with different skills and NP, which made me laugh and choke on my coffee.