Finally managed to get ED1: Wings of Rolldia.
The game has so many questlines with little hints, even with knowledge of Japanese I doubt any first time player would never encounter phases where they just get to wander aimlessly.
Anyways, going to write down my findings so far. Many events seem to be interlocked with each other, so if something doesn't trigger it might be better to go wander around some more I guess.
Probably best to follow the plot flow in the beginning; help out Ilmeia the blue-haired knight save the child from the cave, then follow him to the capital city, meet Frei the court mage and Iriza the pink-haired female knight, be requested to take at least 4 blessings from spirits, and get a house.
Also, I'm going purely off of my own experiences, that has a lot of aimless wandering, so some things may be out of order and/or mistaken.
By the way: doing anything lewd gives you an item with a pink heart icon. You can use this item to greatly reduce EST (100 each prior to 1.03), but prior to 1.03 doing so uses up all charges of the item, so at best you can have one "recovery" in stock.
=Blessings of Spirits=
I've discovered 5 so far:
>The forest of Romenia, at the beginning of the game.
>The forest of Atere, west of the capital city.
>The ruins of Rastera, north of the valley/mountain pass area.
>The ruins of Rishiria, southeasternmost of the map.
>The phantom castle, accessible by talking to the giant dragon skeleton in the southern cave.
After obtaining at least 4, returning to the capital city unlocks the Shrine of Rolldia, where you can undertake the ceremony to call upon Rolldia.
=Capital city sewers=
>Unlock the sewers in the capital city from the bar, and head down there while avoiding/defeating/getting caught by the suspicious hooded people. This event may be a prerequisite for later (involves Ilmeia).
=Bandit Fort=
>Obtain information regarding the bandit-extermination efforts from the capital city bar, and head to the newly revealed barracks and do some sidequesting.
>After a while, the commander should inform you that they have discovered the enemy's base, and is organizing a large scale attack. Accept the request when you're ready.
>Team up with Kurumi and carve your way through the dungeon, getting every single piece of loot you can get. One of them should be a memo containing seemingly random numbers; this will be important later.
=Cult infiltration=
>Not sure when, but after some time entering the port city warriors' guild should have someone approach you with a request; accept, and follow through the event (involves Ilmeia and Iriza). This event may be a prerequisite for later.
=Succubus resurrection event=
>Head to the southeast area of the port city's residential district late in the night to see one of the mook succubi wring a man dry. Chase her down through the dungeon she ran away to, and you'll eventually get the lewd curse. This event may be a prerequisite for later.
>The curse gives you a buff while you have low EST numbers, but ensures that you always have EST buildup over time, and worsens the debuffs of having high EST numbers.
>One of the mages in the port city says that he can probably uncurse you, but he needs a special item from the reclusive alchemist next door who's requesting an assistant to provide him with 100 units of semen. By the way, accepting the job offer from the alchemist also gives you an item that allows you to pretty much prostitute yourself to random town NPCs.
>Not sure how this event progresses later on myself.
>namomo made a post at page 7 that details the questline, so refer to that post please!
=Dilapidated Mansion=
>Not sure when, but talking to one of the NPCs in the northwest village inn/bar will give you a request to investigate a mansion; accepting this request allows you to discover said mansion by clearing the west forest (right next to the capital city).
>Loot everything in the mansion for a bloodstained bracelet and an old book, and return the bracelet to the former maid who gave the request to get your reward. This event is likely a prerequisite for later.
=Otherworld=
>Probable prerequisites: may need to have progressed Ilmeria and Helior's questlines some, must have finished the Succubus resurrection and Dilapidated Mansion events.
>Sleep in the northwest village inn. If all the flags are right, you should automatically wake up to a nightmarish version of your room. Make your preparations and exit the room into an eldritch dungeon. Fortunately, time is temporarily stopped here. Clear the dungeon and return to your usual world. This event is likely a prerequisite for later (involves Ilmeia, Helior and the succubus).
=Rita (red-haired twintailed girl)'s questline=
>Meet her in the western plains (south area)
>Meet her in the port city's warriors' guild, unlock the (south)west cave
>Head to the aforementioned cave, speak to her, party up and clear the dungeon (note: patch notes imply that if you trigger her 'retreat' passive by dipping to red HP around this area something breaks, so you probably should clear this first go).
>Head to the southwest town, to the innermost building, and enter the long line of people; she should be there, right before you. Progress scene.
>Make your way to the northwest village; you should see her in one of the buildings undertaking a request in the northwest forest.
>Follow her to the northwest forest (high danger level; beware of ridiculously fast green ropers), rescue her, and make your way to the end. Watch the scene.
>Return to the northwest village, and watch her complete her quest.
>Not sure if there's any continuation after this, but from now on you can see her in the port city warriors' guild, available for recruiting. She's probably better than the mercenary you can recruit for 50g. Probably. At least she's free.
=Kurumi (oni miko samurai girl)'s questline=
>Meet her in the western plains (south area)
>Finish the Bandit Fort event
>Meet her in the port city bar
>Meet her in the cave east of the port city (danger level 2)
>Make your way beyond the northwest forest to the place with the orb thing and see her there
>Make your way through the labyrinth ruins north of the desert city (danger level 5, stupidly long dungeon. Be prepared.) and enter a strange room with a large statue and 5 smaller statues side by side.
>Interact with the statues according to the order given to you by the memo (so 5 1 3 2 4 for example means that you need to interact with the statues in the order of 5th, 1st, 3rd, 2nd, 4th). If you do it right a treasure should appear. Loot it.
>Talk to her in the port city bar and show her the treasure. Talk to her again when you're ready, to be transported into what's probably one of the most difficult dungeons in the entire game alongside her. Time is temporarily stopped while you're with her, fortunately. Clearing the dungeon ends the questline and awards a Rainbow Crystal, a necessary ingredient in upgrading your weapon one last time into its final form, Sylpheed.
=Elemia (little kid?)'s questline=
>Meet Elemia in the port city bar and agree to help. Elemia will give you advance payment.
>Head to the port city residential district, enter the only enterable home there, and speak to the person there to gain information.
>With Elemia in the party, head to the northern ruins (the place with all the Gazers, accessible from finishing the mountain pass/valley area). Enter the small cave near the end of the area, and fend off the white ropers.
>Return to the port city residential district, and get new information regarding the white rope from the guy there.
>Head to the northwest village with Elemia in the party, and talk to everyone in the inn/bar to gain information. Then head over to one of the houses with the immobile old man (again, with Elemia in the party), and talk to said immobile old man. After the scene you should have a new area unlocked.
>Make your way through the new dungeon, and loot the end room for a key item and a nice hat.
>With the key item and Elemia in tow, return to the place you had to fend off the white ropers for the first time, and head further in. Examine the crystal. Make your way through the dungeon, and you've finished this questline. Not sure if the choice at the end changes anything.
=Lane (detective girl)'s questline=
>Meet her in the desert city bar, and agree to help. Go through the slums and the sewers, finishing the event.
>After some time (not sure), she'll be missing when you next enter the bar. Go through the slums, and unlock the sewers; go through the sewers, to eventually free her and strongarm the local rich man into cooperation.
>Not sure if there's any continuation to this questline.
=Vampire questline=
>Free the vampire from the southwesternmost ruins.
>At night, walk around the southwest town to meet the second vampire.
>Sleep, and after you wake, mr.vampire will request you look for and obtain a certain treasure.
>Maybe optional: at night, walk around the port town's residential area for a second meeting with the second vampire.
>Go through the series of dungeons accessed first via the northeast mining town's mines to eventually obtain the treasure you've been looking for.
>Sleep, and after you wake, mr.vampire will request you go through another dungeon close to the place you first met him.
>Head through the newly revealed dungeon. Boss fight. Unsure if you have to win, but I won anyway. The questline likely ends here.
=Freeing Romenia=
>Probable prerequisites: must have finished the Bandit Fort event, must have helped the detective girl twice.
>If all the flags are right, then the green-armored soldier in the desert city inn will offer participation in the decisive raid to retake Romenia from the bandit force. Say yes when you're ready.
>Clear the dungeon. Note that your magic is sealed for this. You can finally rescue your surrogate elder sister (and view her second H-scene) and take back what was your home for 15 years.
=Iriza (pink haired knight)'s questline=
>Enter the capital city church and see her muse.
>Head to the port city market area, and meet up with her panicking over a stolen pendant.
>Follow her to the western plains (south area) and watch Ilmeia try to calm her down.
>Maybe optional: head to the port city market area again (at night?) and see her grieve.
>(Unsure what triggers the following; you may need to watch the thieving succubi events in the northeast mining town and the northern desert wilderness, and finished the Otherworld event) Enter the capital city church and see her again, with Ilmeia by her side. Leave, and watch another appearance of a thieving succubus. Pursue the succubus to the end of the dungeon. Watch the event.
>After this, she should be always visible in the capital city church, where you can ask her about her stolen pendant. When you obtain the pendant, giving it to her will end the questline.
=Helior (dodgy blonde mage)'s questline?=
>(may require some progress in other questlines) Take a meal in the port city bar. He'll come by and tell you about the whereabouts of his home.
>After getting the Old Book from the Dilapidated Mansion, take it to him in his home, and he'll trade it for 1000G.
>After some time (unsure; Otherworld may need to be finished) wandering in the west forest (right next to the capital city; you needed to get through there to unlock the mansion, and it's the location of one of the blessings you need to take) will have you encounter him for some lore talk.
>Head to the northern ruins (the place with all the Gazers, where you needed to take Elemia to, accessible via the northern mountainpass/valley area, also is the location of one of the blessings) for another encounter with him and more lore talk.
>Head to the southeastern ruins (yet also the location of one of the blessings) for the third encounter with him and even more lore talk. He should give you his home after this.
>Head to his home. Examine the sparkly. Obtain the Locket Pendant. The plot thickens.
ED6: is given to you when completing Kurumi's questline.
ED5: is given to you when completing the Vampire's questline.
ED4: is given to you when completing Elemia's questline.
ED3: is given to you after retaking Romenia.
ED2: is given to you if you undertake the ceremony of Rolldia's descent before finishing Iriza's questline.
ED1: is given to you if you undertake the ceremony of Rolldia's descent after finishing Iriza's questline.
You may also consider ED1 the true ending and true final boss.
