So I really think it would be awesome to make a Return to Kamigawa set, but I don't know enough about the characters. From my understanding, Toshiro Umezawa led the rebellion against Konda who started the Kami War by stealing That Which Was Taken to make himself/his daughter immortal. And the Myogin of Night's Reach was like really important somehow. But like what about Meloku the Clouded Mirror? How many of the awesome cards that really resonated with the players (e.g. the dragon cycle) actually came thru as important in the story?

Hey Parad, welcome to AF&S! Always glad to see some more Kamigawa love!

Meloku played a small but crucial role in that he and Hisoka, Minamo Sensei helped Konda to kidnap That Which Was Taken from the spirit realm. IIRC he didn't do that much later on in the story, though the soratami were kind of involved in a plot by Mochi, the Kami of the Crescent Moon, who really wanted to piss off O-Kagachi, the Great Kami of Everything to make him wreck the mortal realm and shake things up or soemthing like that. Notable allies of Toshi's were Kiku, Night's Flower, Marrow-Gnawer and of course Heartless Hidetsugu. The latter destroyed Minamo, School at Water's Edge together with the All-Consuming Oni of Chaos and bit off Hisoka's head. In the battle of Minamo, Hidetsugu's oni also killed Keiga, the Tide Star who was the school's defender. Yosei, the Morning Star is also featured in the books, he is summoned by Konda to defend Eiganjo Castle but is torn to pieces by O-Kagachi. Characters like the Brothers Yamazaki or Ben-Ben, Akki Hermit have cameos, too. Kiki-Jiki, Mirror Breaker doesn't show up in the novels but is featured in a short story (that I can't access right now because their server crashed apparently...). Michiko Konda, Truth Seeker and her "sister" Kyodai (the form That Which Was Taken takes after it/she is freed by Toshi) kill O-Kagachi, redefine the boundaries between the two relams and become the new guardians of Kamigawa.

The metaphysical changes to the plane also mean that mana becomes more accessible on the plane at the end of the trilogy and people rely more on "real" magic rather than prayers to the kami. The kami don't manifest as often anymore and basically retreat to the land itself, which means you have to appease them first when drawing mana from there. This is also shown in Jace's planeswalker novel Agents of Artifice where he does a short trip to modern day Kamigawa. Kaseto, Orochi Archmage seems to be from this modern period as well.

An important thing you have to keep in mind is that the Kamigawa block and trilogy happened some 860-ish years ago, so presumably a lot has changed on the plane and most of these characters are long dead and wouldn't show up again. Well, the kami obviously might because they're ageless spirits, and we don't really know for sure whether you can truly kill them, so there's that. Fan fovourite Hidetsugu merged with his oni at the end of the trilogy btw, so he could totally come back, too. This odd placement on the timeline stems from the fact that the Kamigawa trilogy is a quasi-prequel to the Legends II cycle, which follows Toshi's descendant Tetsuo Umezawa several hundred years later (Toshi is blinded and sent to Dominaria by the Myojin of Night's Reach as a punisment for disobeying her at the end of the trilogy, so he ends up founding a line of Umezawa's in Madara). This thread is picked up again in Time Spiral when Nicol Bolas breaks free from the prison he was put in by Tetsuo, planeswalks to Kamigawa and vows to erradicate the Umezawa line out of revenge. I like to think that some descendants of Toshi's that don't bear the name Umezawa still exist on Kamigawa (*cough*possible planeswalker*cough*), though, because Toshi had sex with Kiku during the third book, so it's theoretically possible she got pregnant...

The spark for everything was Mochi, the Kami of the crescent moon tricking Lord Konda into wanting to steal a part of O-Kagachi, the spirit manifestation of the entire freaking plane. (I believe Mochi sent him a dream.) This makes Konda immortal and stops Kami from attacking his castle, Eiganjo so long as he controls that which was taken. The Minamo school and the moonfolk (who Mochi works for) were vital parts of the plan.
This was only made possible by the birth of Konda's daughter Michiko causing an outpouring of sympathy from the spirit world (or something like that). Of course it also prompted the spirit world to wage war on the mortal world. The mortals keep getting the worst of that and everything goes to hell, but Lord Konda is irrationally confident about the whole thing. It's important to note that nobody on either side seems to know just why the war started; diplomats just weren't a thing I guess.
When Michiko grows up she wants to find a way to stop the war so she escapes here father's castle in search of answers. I believe Mochi, the Kami of the crescent moon had a hand in this as well.
Toshi Umezawa was doing his own thing when he met up Michiko and friends. They were both captured by Orochi. Michiko and Toshi end up working together, but a spy in Michiko's party kills Toshi's companion. Unfortunately, that companion was Hidestsugu's apprentice. Hidetsugu vows revenge on not just the murderer, but the people he works for- the Minamo wizard school. This is very bad for Minamo. Mochi and the Myojin of Night's Reach try to get Toshi in on their scheme but he doesn't trust them and sticks with the princess.
Without its mystical protection (I think that which was taken was removed, or else Michiko needed to be there for it to work properly) Eiganjo gets sacked by O-Kagachi itself. Place doesn't really matter any more though.
Toshi, Michiko and co. start unravelling the mystery of why the war happened and how to stop it. This takes them to Minamo, a place to which bad things will happen. Hidetsugu and his followers reach Minamo, and they kill like everybody. Big H takes revenge seriously. He probably would have killed all the moonfolk too if he had a chance. Toshi calls out his old bud Hidetsugu for being the worst guy ever and I don't really remember what that amounts to, but Toshi wins. The Myojin of Night's Reach is super mad at Toshi for messing up its schemes and banishes him to Dominaria.
Michiko and That Which Was Taken are both in Minamo, so O-Kagachi shows up to reclaim TWWT. Hidetsugu tells his master, the oni of chaos to attack O-Kagachi, by the oni chickens out, SO HIDETSUGU BEATS UP HIS OWN GOD FOR BEING TOO COWARDLY, proving that Hidetsugu is awesome. Michiko unties with TWWT to become one being. They decide O-Kagachi sucks and they would rather be in charge of maintaining the balance between the spirit and material. They essentially beat up and absorb THE PHYSICALLY MANIFEST SPIRIT OF EVERYTHING. Super Michiko fuses Hidesugu with his old bud, the all-consuming Oni of chaos because somebody needed to fill that role and they wanted somebody who wasn't pathetic. Mochi tries to brown nose the new boss, but gets called out for starting the whole dang war and I'm pretty sure he gets killed. The end.

I believe the Moonfolk were being played by Mochi, who wanted to become the supreme being himself. Konda planned to rule forever as the best ruler ever because he was tricked by Mochi and the Moonfolk. Konda kept the rest of the world in the dark about the whole thing. O-Kagachi never bothered explaining its motives. And bajilions of people died before Michiko could set things right with Toshi's help. Of course Mochi and the Myojin Of Night's Reach wanted to trick them too.

http://mtgsalvation.gamepedia.com/Outla ... f_Kamigawa

**** right I'm awesome.

You know, your synopsis, TP, reminds me. I never understood why Mochi would want O-Kagachi to manifest in the utsushiyo. Perhaps Mochi had hoped that Konda or Hidetsugu would end up killing O-Kagachi once it manifested in a fleshly form?

Oh my god it's him! He's here! Ok TP, keep it cool in front of Big H.
I think Mochi wanted to get its hands on That Which Was Taken and possibly from there use it to absorb O-Kagachi or something. I'm not too clear on that point.

Seems plausible. The Soratami attack on Jukai also seemed random. I guess they wanted to snuff out what they considered the greatest threat to their plans for Kamigawa?

I thought they were removing witnesses. Or was the attack before that? If that's the case I have no idea.

Witnesses to...?

If I remember correctly, the attack on Jukai wasn't until Saviors of Kamigawa's novel (third in the block for the OP). Just looking at the orochi in Champions of Kamigawa...I wonder if the soratami weren't just trying to remove the biggest threat to their plans. In CHK, when the Myojin of Life's Web said "jump", the orochi always responded "how high?" whereas people like Toshi and Boss Uramon would usually only go with Night's Reach's orders if they stood to gain from them...so I suppose the inflexibility of the orochi made them too dangerous for the soratami.

I'm not even sure what I was referring to when I said "witness". I think the Soratami wanted to take out Toshi's group for seeing something they shouldn't have, but the actual attack on Jukai? I have no idea.

You're right about the witnesses thing - Toshi interrupted one of Marrow-Gnawer's Soratami-sponsored operations. From there they kinda started chasing Toshi.

I think my favorite scene from any magic novel is the Betrayers prologue where Konda's samurai silence a couple of dissenters in the assembly - right before he summons Yosei the spirit dragon.