When Mei's older sister Izumi, also known as the saviour of the Ransei region, dies from illness, she is devastated, but must take over as warlord of Aurora. Oichi is no help, and has refused to talk or even eat or sleep since Izumi's death. When Mei and her Dratini Miu are attacked by Mitsunari, the new Warlord of Ignis. She falls to him, and Aurora is taken. After she wanders for a while she meets him again and he offers her Aurora back as an unlikely friendship is born.
Mitsunari and Mei form an alliance, but Mitsunari's friends Kiyomasa and Masanori, now Warlords over Greenleaf and Fontaine respectivley, have fallen for Mei! Mei is flustered and doesn't quite understand how this warlord thing works yet, so the three decide to help her out. With Kiyomasa and Masanori constantly putting the moves on her, Mei's head is spinning! After a training session in Greenleaf, Miu evolves into a graceful Dragonair and soon sets her sights on Mitsunari's Bisharp. Bisharp doesn't really respond to all the extra attention given by Miu, and Miu is slightly glum until they win a battle with the kingdom of Chrysalia in a Warlord collaboration contest, and Bisharp is so happy he kisses her. Miu is happy, but suddenly realizing what he's done, Bisharp suddenly denies he did it ("B-Bi. BISHARP! Bisharp bish bi bi bish bish bisharp bi! B-Bi Bisharp...") and Miu becomes glum again, though not seeing Bisharp's face fall as well. Mei is starting to make plans to get the 2 together and is trying to get Mitsunari to help, but he refuses. ("No matter how good of a friend you are Mei, I am not helping my pokemon with his love intrest! Arceus, if he doesn't want to have a romantic relationship with her, he doesn't have to!")
One day, Kiyomasa and Masanori start an ongoing war with eachother, where the first one to 3 wins is the victor, and the prize was to be able to go after Mei. One problem, no one got Mei's consent and she freaked out when she found out she was now a prize. Mitsunari calmly steps in and crashes the 2nd battle with Mei, and explains that she is not a prize and this needs to stop. Mei nods her head, confirming the words to the bitter teens on either side of the field. Kiyomasa and Masanori decide to team up to take on Mitsunari, but Mei exclaims that isn't fair and becomes Mitsunari's aid. He nods his head in gratefulness before they fight against their enemies. After the battle is finished and Kiyomasa and Masanori proven stronger, Mei has no choice but to watch their final battle, wondering which one she will have chasing after her sadly. Miu growls gently beside Mei as she strokes the blue fur softly, bitter that she couldn't win the battle. She didn't want Mei to be chased, and she knew this battle, when it got to 3 wins on one side, would just be extended and the fighting would never stop.
Mei grew tired of the fighting over the months, and, as Miu had silently warned, it was now who won 15 out of 15, and just kept extending. Mitsunari would sit with her in Aurora, and the 2 would talk about how to stop it and restore peace to their section of the Region. Soon it became too much, Ransei was falling into crisis yet again as Kiyomasa and Masanori's battle raged on, and they began taking over other kingdoms, their motives not even to get Mei anymore, but to defeat the other. One by one the kingdoms began to become ruled by one warlord or the other. They took it up to Dragnor, going so far as to begin to climb the tower, trying to get there fastest. It would take them at least 2 years to get up that tower, and Mei decided it was time to follow in her sister's footsteps and take a stand to re-save Ransei. Mitsunari refused to let her go with only Miu by her side, and he and Bisharp agreed to become her co-warlords, even getting some warriors from Ignis to help.
As Mitsunari and Mei grow their Army, they get closer to the tower at which the rivals are climbing at insanely fast speeds. They stopped for almost nothing, but decided on a foot race with no cheating. Deadly traps were of course placed everywhere though, and though they were fast, the traps slowed them down. When Mistunari and Mei finally made it to the tower, Mei was scared and looked to Mitsunari for comfort. He smiled reassuredly and grabbed her hand, Miu slithering close behind as Bisharp sprinted ahead. The 4 made their was carefully through the tower, and rested. Mei and Mitsunari would sleep on the floor for short periods of time throughout the day. For every hour and a half of running, half an hour was spent sleeping. They worked day and night, but Mitsunari and Mei didn't give up. Bisharp decided to finally accept his crush on Miu too, and the two of them stuck together, fending off wild pokemon and warriors ahead while Mei and Mitsunari ran behind.
Eventually, about a month later, they found theirselves at the top, but it wasn't just them. Kiyomasa and Masanori were there too, and were having another battle at the top, their pokemon of matching strength. Mei ran to the middle of the field, Miu slithering foreward as she let out a shrill whistle. The battle was stopped for a moment before Mei began speaking. She yelled that it had to stop and told them to look at the damage they'd caused. They were as bad as the evil vanquished by her sister, she had told them. They were almost crying. Masanori tried to throw himself off the top of the tower, and ended up doing just that even though his two friends had run over to try and stop him, as well as Mei. He just said he didn't want to live with the pain of doing this. Kiyomasa and Mitsunari cried silently as Mei tried to comfort them, she knew how it was to lose someone. Oichi had taken her life two months after Izumi's death too. Kiyomasa released the kingdoms back to their owners, and took responsibility for fixing the repairs. He then became the warlord of both Greenleaf and Fontaine after going far and with to explain the events of the past 4 years in detail.
As for Mei, she went back to the way things used to be. Ruling Aurora with a caring and generous hand. Mitsunari missed their partnership, however, and decided to make a special request made only once before. Conjoin the kingdoms of Aurora and Ignis together into a kingdom called Isenfree. Mei agreed wholeheartedly, and they became great Warlords, Mei with strength and kindness and Mitsunari with wisdom and strategy, always protecting their kingdom. Kiyomasa stayed their friend and alliance, and had lost his infatuation with Mei years ago. The three liked to talk over a meal, and were always happy to have a friendly battle or two, since they were evenly matched. Often Kiyomasa would joke about how Mei and Mitsunari should just get married or something, in private of course, he was sure if Mitsunari were to hear he wouldn't be to happy, but maybe Mei would be okay with it. He didn't want to risk it.
Kiyomasa decided that he should do something when Miu had her eggs and he was gifted one, yet the warlords were still not together despite the fact their pokemon were already reproducing. He had quite enough of this silliness of ruling a kindom together, and even sleeping in the same room, and yet not being a couple. Kiyomasa was not one to play matchmaker, but this time he felt it necessary. He began by pulling aside his childhood friend, inquiring him about their relationship, to which he got an eye roll and a sour 'Will you stop? We're just friends, so I don't understand why we can't be just that.' From Mitsunari. Kiyomasa did notice the faint blush on his cheeks though and chuckled to himself, earning a glare from Mitsunari, who's blush had just doubled in color. Kiyomasa decided his next motive was to focus on Mei. He went over and had tea with her, asking her too about the relationship between the two. She shook her head politely, saying she didn't know how he felt about her in that way, but she didn't think he would ever like her back. Well, in that way at least. She did admit, blushing, that she liked him in that way, if only a little bit, but was too shy to say anything. Kiyomasa smiled and told her to go for it, and she smiled back with a thank you, but told him that, as she said before, she was too shy and he probably didn't like her back, if she was ever going to tell him, it would be when she was a braver person and took defeat in the romance catagory more easily.
And so Mei and Mitsunari remained friends. Kiyomasa eventually gave up trying to get them together and Mitsunari forgot his grudge against his friend. Kiyomasa had just challenged the joint Warlords to a battle when Mitsunari said they wouldn't be able to do a battle right now because Mei was sick. Kiyomasa quickly made his way to Isenfree and Mitsunari let him inside. Mei lie on the bed, very sickly looking. Kiyomasa was surprised, Mei wasn't usually sick, but Miu was curled beside her protectively and murmuring softly. Mei didn't usually get sick, but when she did, it was bad. Mitsunari sat beside her and wet a rag, pressing it firmly against her forehead as she looked up sleepily and gratefully. She smiled before falling asleep, and Mitsunari sighed, placing the rag back into the bucket before re-adjusting Mei's sheets. Kiyomasa chuckled again as Mitsunari blushed lightly, looking at his sleeping friend's face before glaring at Kiyomasa again and going to go check on the people to see if they needed any help with bandits again or anything. Kiyomasa just shook his head, when would those two realize that their partner was also in love with them.
After Mei had recovered from illness, she was back on her feet again. Mitsunari was very very pleased by this. Kiyomasa re-challenged them to a battle, this time he spoke to them beforehand, asking for a bet. If he won, they had to become a couple. Mei just blushed, but Mitsunari yelled some choice words into the phone before hanging up and asking Mei to remind him never to do a battle including a 'mystery bet' with Kiyomasa ever in his life, and Mei, though a little bit but barely noticeably crestfallen, agreed and made a mental note of it. Mitsunari had been trying to make up his mind about telling Mei how he really felt about her, he imagined if she really did like him in that way, she was a little bit hurt by his actions back there. If only she knew. Mei, too, wanted to tell Mitsunari how she felt, but was still shy. Eventually Mitsunari pulled Mei aside, after they were done with tending to their loyal warriors' needs. He told her they needed to talk, so she oblidged and sat with him. He didn't really speak, just reached foreward, hugging her as she opened her eyes, for it was a shock, Mitsunari was never really... Affectionate. He preferred to show they were the best of friends by talking. She stayed silent too, and reached out her arms to hug him back. He smiled with a whispered 'I love you' as Mei's eyes felt like they were to pop out of her head. She couldn't speak, so she hugged him tighter, feeling his grip tighten too.
Soon they were a couple, and Kiyomasa tried to take all the credit, though appointed only partial credit by Mitsunari. The Warlord couple kept ruling their kindom with their respective qualities, and were (Within a few years) married. The trio grew old together, and though their deaths were mourned by many, Bisharp and Miu knew that their legacy would live on, and everyone would be reunited under reign of Arceus. As the pokemon cuddled with eachother, they watched over their eggs and the city of Isenfree, a young boy, randomly selected, was chosen to watch over Isenfree, and a young girl offered to join him. Thus the legacy of Co-Warlords kept going.
And Miu was right. Mei reunited with her sister, who somewhat disapproved of her marrige to Mitsunari becasue of the way he treated her in the past, but once she saw he had changed she deemed him worthy for her sister. Oichi was smiling again, happy as always and standing beside Izumi, Wigglytuff and Flareon playing. Mitsunari and Kiyomasa met up with Masanori and the three wept with joy, for they were reunited. All was well, both above and below the cloud layer of the Ransei region.
All was well.