I'm playing the Korean version right now. It was sorta troublesome to register for, but...
Anyway, it's surprisingly fun. I can't read Korean but I've been figuring it out as I go along.
With some exceptions, every card in the game, it looks like, is either a maid, a vampire loli, or a schoolgirl. Even the spell cards fit one or more of these categories. No armored girls, unfortunately, but they do wield swords or whatever (maids get brooms etc.).
Cards are split into four factions:
Public School: Yellow like Refess. A bunch of high HP defensive schoolgirls.
Academy: Red like Gowen (don't know if coincidence). Maids led by the generic rich blonde foreigner mistress it looks like IDK. This is the faction I picked.
Crux: Blue like Falkow. Schoolgirls. Typical high AT jerks with OP abilities. Should have been red.
Darklore: Purple like Lawtia. Vampire lolis and witches led by an eyepatch girl. This is the faction I should have picked.
Gameplay is pretty straightforward. You can either battle against NPCs by running dungeons, which can be surprisingly challenging, or fight against other players. Each card has a "level", called "Size". You can set up to 5 cards from your hand to the field every turn with a total aggregated size value of 10 or less. After the set phase, each card takes turns activating. A spell card activation usually provides buffs to friendly units or debuffs to enemy units (though sometimes they do weird things like sending your own cards to your opponent's hand (I guess to clog up his draws?), or manipulating Size values to give yourself more space to play higher Size cards the next turn), after which they disappear from the field. A unit card activation is much simpler, it just means that the unit attacks another random enemy unit (though some unit cards have abilities).
Each unit card has Attack, Defense, and HP values. When a unit card attacks another unit card, the second card's Defense is subtracted from the first card's Attack, and then that value is subtracted from the second card's HP. Basic stuff. If the second card survives the attack, it counterattacks the first card. I guess this is to make things more fair because activation order is based on a coin toss. But this also means that you can just buff up a single unit to disproportionally strong levels by using your Size allocation to spam +Attack/HP spells every turn, and then solo the enemy field with that single unit by relying on counterattacks. That's pretty much what Sword Girls meta is, rushing out a couple Size 3-4 units that start off with like 7 Attack and 5 HP then buffing them up with Size 2-3 spells every turn and by turn 5 or so you've got two 30 Attack 30 HP units on the field steamrolling over the opponent's entire deck. It's actually really refreshing to be able to use buff cards without having to constantly worry about getting returned.
Matches last 5 minutes or so, as opposed to the sometimes 30+ minute matches we get here in Alteil. This can be either good or bad depending on how you look at it; matches have less strategic depth but are much more relaxing to play through and it's a lot less disappointing to lose a 5 minute match than a 30 minute match. What I really like about Sword Girls, though, is the fact that you can actually GET cards as a free player. And by getting cards I don't mean playing some irrelevant minigame every day for some useless 1* or like, one playset of a couple EX cards after multiple months of saving up, I mean actually being able to GET cards and GET the cards you want by PLAYING THE GAME. And by playing the game I don't mean grinding hours and hours for 625 hours worth of FM for a single high rarity card or having to play 500+ matches just to get to your next levelup rewards screen, I mean ACTUALLY GETTING the cards that you WANT by PLAYING THE GAME for only a couple of matches.
When you battle NPCs in dungeons or when you fight against other players, you get materials (and against players, you don't even have to win the match to get materials, as long as you played through the match and didn't quit halfway through you get the same amount of materials for losing as you do winning) that can be synthesized into specific cards that you choose. For some cards it only takes about 2-3 matches worth of materials, though for some of the higher-end cards it takes 70-120 matches, because those cards require other cards as ingredients, and sometimes those ingredient cards require other ingredient cards (it does get sort of ridiculous trying to keep track of all the things you need). But keep in mind that these are 5 minute matches. If you're dedicated, you can get a top meta deck in only a week.
There's also some sort of "card training" feature where you select cards to train over a certain period of time that I'm guessing eventually improves their stats? IDK. The tutorial quest explained this but Korean is more confusing than moonrunes for me. It also doesn't help that the online FAQ and Game Guide aren't text, but IMAGES of text, so you can't even copypaste it into google translate or something. Ugh.
Anyway. It's a fun game with cute art. It'd probably be a lot more fun if it was in a language I could read, or at least copypaste, because right now I've no idea what's going on.
Oh yeah, Multi, I had to add a friend for one of the beginner quests so I added Multi. I hope that's you. And if you could explain to me what exactly that quest was about because I still don't get it, that'd be great.