Ironically, this is a guide that results from ScorpiusG's guide that resulted from my other guide to this game.
https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=882992198
And it started out much the same way as that one did!

Having gotten to the Axel Mode (and somewhat painfully through the last handful of stages up to 3-4, due to my good characters mostly being Adell, Hanako, and Taro - ack!), I read ScorpiusG's guide and found it damn good.

But of course, it has its limits - it levels one person pretty well, but if you need to get a whole army leveled up for some reason, you have one of two choices. One, level up one character so powerfully that they can essentially lead others through Cave of Oblivion 4 by the nose, or two, find a way to get a whole army steadily better.

And so I found a way to do the latter!

This guide will show a method to level up seven (potentially eight... maybe?) characters at once using Axel Dark World 3-4. It uses essentially the same strategies as ScorpiusG's guide, so all the credit goes to him for that base strategy. The end result differs, however - as opposed to one character getting all of the experience and Mana from the kill, the characters you level will all split the experience and Mana of the Archer, thereby letting them level up in a more level and controlled fashion, as well as letting you have enough Mana to begin reincarnating, improving their counters/movement, and so on.

Sound good to you? Then it's SHOWWWWWTIME, baby!

You'll only need a few things to actually achieve this strategy.

1) Pass the Strongest Enemies Bill. You want that Archer at Level 9999 from the get-go, since this will take all of three turns to do, and waiting for her to level up is going to be extremely nasty to you due to the Dark Sun. If need be, follow ScorpiusG's guide a few times to get someone more than enough Mana to pass the bill - both raising and lowering enemy strength rarely fails to pass, and doing it even once makes the Mana cost for either of these bills negligible.

2) You will need at least two Kunoichi. They can be unlocked by having someone with Level 5 Fist Mastery and Level 5 Staff Mastery, then pass the "Make a Kunoichi" bill in the Dark Assembly. If you've played through Adell mode first, you likely already have them, but if not, they are absolutely required.

3) One of those Kunoichi will need to have 8 movement. This can be done by giving them three pairs of shoes; any kind will work. If you've got an Accelerator, that will also work nicely, but this Kunoichi really won't need the other boosts of it, so just grab three cheap pairs of shoes. If you don't have them, pass the Shoe Inventory bill in the Dark Assembly if you haven't, for some reason.

4) Both Kunoichi will have to be at least Level 15, to know the skill MinMinMin. If you don't have this, simply make use of ScorpiusG's guide to level them up to that (and more) in two runs.

5) You will still need at least one Thief who knows Freedom - thus, that Thief must be Level 20. Irritatingly, a Kunoichi can't use Kagenui to sleep the Archer due to it needing an extra open space - that is killed by the No Entry Geo Effect. Hence, a Thief who knows Freedom is still required, but you can generally keep them safe until you actually need to use them, making the strategy a fair bit more tolerant of the Dark Sun going crazy with status effects. Personally, I have no idea why Kagenui has to be so restricted when literally every other Kunoichi skill is free-select cross shaped... but I digress.

6) Probably the trickiest to get: You will need a Fist User with Level 15 Fist Mastery - and obviously you can't cheap up the skill levels without plenty of Armsmaster Innocents. This will probably be, of course, Axel. Technically later on this may NOT be required, but until you can deal tens of thousands of damage to a Level 5040 Geo Symbol, yes, you will need this. That said, as long as you've used him a decent amount up to unlocking Dark World 3-4, you may already have done this.

All set? Then let's begin.

1) Check the Dark Sun report. If your FIRST TWO TURNS are going to result in a Paralysis or Sleep for either males or females, reset and reload. It will mess you up. Anything else - poison, curse, you name it - is fine, but you cannot have Paralysis or Sleep. Female Amnesia is tolerable (you have a spare Kunoichi for a reason!) but it may get a bit tricky and you may have to burn an extra turn to Espoir them as a result, since you will be wanting to re-cast sleep on the Archer every round. Male Amnesia is also something to watch out for - it will mean you will be delaying several turns until it wears off, but as long as you can withstand that, you are also fine.

2) Send out someone who will throw your first Kunoichi over the border. This can be literally just about anyone, but I tend to use Axel. Plonk them right next to the Base Panel, since you can't grab anyone or throw them except right off the Base Panel.

3) Get your Kunoichi out. This is the one who will need a Movement of 8.

4) Have Axel throw her over the border on the left using the "No Entry" throw trick (as mentioned in ScorpiusG's guide) to land directly outside of the No Entry border, then have her use MinMinMin on the Archer from where she lands.

5) After the Archer is asleep, begin moving her towards the Deathblow Geo Symbol.

1) Return Axel to the base panel if you used him to throw Kunoichi 1 out as I had, then get a second thrower out, throw Axel (or whoever your 15 Fist Mastery Fist user is) out of bounds in the exact same spot as the Kunoichi, and have him begin walking straight towards the No Lifting Geo Symbol.

2) Kunoichi 1, thanks to her movement boosts, should now be able to reach and throw the Deathblow Symbol into the blue panels (again via the No Entry throw trick), setting up the one-hit kill for the Archer.

3) Have Kunoichi 2 come out of the Base Panel and MinMinMin the Archer, putting her back to sleep.

1) Keep moving Axel towards the No Lifting Symbol. He won't have enough movement to reach it, but...

2) Kunoichi 1 can now move again. Have her move next to Axel, pick him up, and throw him right next to the No Lifting Symbol.

3) Axel can now use Rising Dragon on the Symbol - even if the attack misses or does no damage, it will still force it off the blue panel, and behind Axel.

4) With that pesky No Lifting Symbol now no longer a problem, you can begin to build a tower. You will need at least a tower of 2 to hit the Archer, and due to the 10-character limit, along with the three characters who are otherwise being used in some capacity, you have a maximum tower capacity of 7, since you need both one character left, and one spot open right next to the Archer.

5) Determine how many characters you want to level. If it's an odd number, start by putting someone right next to the Archer, then having them lift the person behind them. If it's an even number, you still want to put someone next to the Archer, but have the character who's next to the Base Panel lift the one in front of them (next to the Archer) instead. Alternate back and forth between these as necessary, picking up your desired stack of characters.

6) Bring out your Thief, and use Freedom on the Archer. This is why the lifting order is important - regardless of how many characters you wind up with in your tower to level, it must end with the space in front of the Archer open for the Thief to operate successfully. Basically, no matter how many you have in your tower, the spot directly in front of the Archer MUST be clear for the Thief to do her work!

7) With the Archer now paralyzed, thanks to your tower, you can attack her even though you're behind the Thief! Go ahead and Tower Attack her.

8) Watch that high damage number roll up. Archer dies. See lots of "Level Up" texts. Smile.

This strategy, much like my other one for Adell Dark World 3-3, likely has some room for improvement.

1) The most obvious one would be instead of needing a Fist User to move the Geo Symbol, that the Kunoichi you throw out there is also strong enough to kill it outright, or to have enough Fist Mastery of her own to use Rising Dragon, negating the need for you to throw out Axel or another Fist User. That would increase your tower to 8 characters, but you would still be out two - a Thief is needed to paralyze the Archer, and your Kunoichi who threw/killed the Geo Symbols is still trapped outside of there.

2) If a way could be found to remove No Entry somehow (Mages/Skulls with ridiculous cast ranges?), you could have the Kunoichi outside use Kagenui to Paralyze the Archer, allowing you theoretically a tower of 9, since you wouldn't need your Thief anymore - the Kunoichi who both threw Deathblow and killed/moved No Lifting could simply come back down and use Kagenui to paralyze the Archer. However, since the only ways I could think of would require throwing out another character to the right to negate the No Lifting Symbol, then having them get back to the base (eating up turns all the while), it's questionable whether it's worth it just to get them an ever-shrinking slice of a pie.

3) Leveling Monsters is a simple matter of Magichanging them with a human before their human does some lifting. That said, remember that this will also consume a character slot, so you may need to plan your tower accordingly.

Anyway, that's it for this guide! Again, I want to give a big thanks to ScorpiusG for his own guide on the subject. Without his work, this itself may not have been possible.

If you've got any further ideas for how this strategy could be simplified or otherwise improved, feel free to drop me a message and let me know! Good luck with your leveling!