You were Jack Lantern, a freshly full pledged member of the infamous rogue guild in Mallow Kingdom, Scavenger. The guild took you in when you was but a boy, living in the street, pickpocketing people for living. Now the guild was not particularly noble, the members were sellswords, mercenaries if you may say, that would do most job with proper payment. But that could be considered as honest work in this dangerous and cruel world, and they despised thieves despite being called a rogue guild. Long story short, the reason was that they had a bitter past with a certain thief guild. They took you in, taught you well, and now you were ready to become one of them. But you had to make a name for yourself and gained a lot of experience before you could take the guild's mostly-dangerous official missions. So they sent you out alone, to return when you had enough experience.
You then went to the nearest town to find some work to do. That was when you met her. Crystal Wintermonth, the wandering priestess. Her mother was an ex-high priestess, once had a place in central church, famous for her skill in spearman-ship, until she was banished for committing adultery. Hence, she lived in seclusion, raising her daughter by herself, teaching her everything she knew. Since they rarely met other people, Crystal grew up to be a timid person. However, one day she found out that her mother was ill. She still could do day to day activities, but the sickness slowly was eating her health away. They barely had any valuables so they couldn't afford any healers or medicine. Crystal knew she had to make money if she wanted to stay with her mother longer, so with her mother's blessing (although she was reluctant at first), Crystal went away.
Being timid, Crystal found that it was difficult to find a job since it required communicating with other people. Her mother also told her that it was better to have a companion, but she wasn't even able to properly order a drink at the inn, let alone finding a partner in arms. That was when you found her. Being a beautiful young girl, Crystal often got harassed by perverts, and that day at the inn was no different. Crystal could only helplessly fend them off unsuccessfully, surrounded by those beast when you entered the inn.
Once again, the guild Scavenger was not particularly noble, but they did have several ethic codes to be obeyed by all members. One of them was to help any encountered damsel in distress (and if possible, to ask for something in return later). Following the code, you went to help her. No violence was involved. By merely pretending to be her close friend, you made the offenders hesitated when they saw the Scavenger insignia on a scarf, tied on your right arm. Being in a famous guild had its perks as they slowly left you two alone.
Later, in a very quiet voice you almost couldn't hear, Crystal thanked you. You asked what her business was in that village and then you two traded some stories. You were a little disappointed that you couldn't get anything from a poor priestess, but you welcomed Crystal to accompany you to find jobs. As your teacher always said, the more people in your group the better, especially if they were beautiful girls. Your teacher was a huge pervert and it somewhat rubbed off on you. Crystal was overjoyed by your invitation, but once again failed to properly thank you.
That was a couple of weeks ago.
*****
You groaned as you slowly regained consciousness. You couldn't believe you were that careless. To fell to such attack, your teacher would kill you if he found out.
"That damn animal is going to pay," you silently promised inside.
As you opened your eyes, you tried to sit up. You felt something were off but couldn't figured out what. Your head hurt as hell, so you reached out with your hand. Instead of your short shaggy hair, though, you felt silky smooth hair on your hand. Surprised, you retracted your hand quickly that some of the hair flung out into your vision. They were long, which was not how it supposed to be, and instead of black, it was blue-ish white. You looked blankly at your now slender hand. Then you looked down and saw them, a pair of breast pushing through a white blouse.
"What the..."
You started to say, before snapping your mouth shut. You recognized the voice that went out of your mouth not as yours, but of your 2 weeks old companion. You looked around and finally saw another body lying down which looked like you. In fact, it was your body indeed.
"You've gotta be kidding me..."
Somehow, you ended up in Crystal's body. Well, the 'how' part was actually quite obvious. It must be that monster's vault. The real question was, what happened to Crystal.
You took a deep breath, trying to calm yourself down. Then you got up and approached your body. It was you, alright, still in your black shirt and trousers. It appeared to have no injuries, as with Crystal's body. You then shook it, feeling a little relieved when it started to wake up. After it opened it's eyes, it quickly sat up and looked around. When it finally saw you, its face showed horror and disbelief.
"Crystal?" you softly asked.
The response you got was a loud shriek and instant back jump, before crawling on all four. Several short shrieks followed after it turned back to see you.
"Yep, that's her," you sighed inside.
It might be only 2 weeks, but you got to spend a lot of time together so you knew most of her behaviour already. Your teacher taught you how to read a person's personality, anyway, which helped much. Crystal was still screaming, by the way.
"Crystal, please stop screaming with my voice, it sounds... Weird..." 'Pathetic' was the word you wanted to say, but you decided against it.
She soon stopped. But it seemed that Crystal had just realized the condition she was in as she now looked down on her body, seeing your body instead of hers, and then continued her screams. Her screams made your headache worse, but you wouldn't even bother telling her to stop again. Eventually, Crystal calmed down somewhat.
"J-jack?" she stammered, which you replied with a nod.
"Wh-what happened?"
"Must be that last attack... Probably it was its special power or something, and it made us swap bodies like this"
"N-no... I don't want this!" Crystal started to panic again.
"Calm down, we will find a way to reverse this... Maybe we can figure it out if we captured that beast... But it will be difficult..." you pondered.
"You... You seem very calm about all this..." Crystal said to you.
"Hmm? Well, you could say, I have somewhat plenty experience about this kind of thing," you said while smiling bitterly.
Your teacher had a close friend who was a wizard and whenever they met up, your teacher always tag you along. They often made you his guinea pig, trying out new potions and spells he made. Most of them were successful, unfortunately the effects were as ugly as intended. One time your nose grew very long, other time you grew a pair of goat horns, another time your skin turned into rainbow color, once you were transformed into a dog for a full day, etc. They never turned you into a girl like this, though, which was surprising since that wizard was as perverted as your teacher.
Bottom line was, there were many unpleasant things happened to you, but they were all reversible, so this one must be too. That's what you believed.
"We will try to capture that one, but I don't think it is going to return to the farm soon, so we will have to find it inside the forest," you told Crystal.
"Well then, l-lets go..." she said while standing up.
"Hold it, it is way past noon. It will be dark in a few hours. We better start looking tomorrow. Besides, there is another important thing to do"
"W-what is it?"
"Tell me, do you know how to use a sword?" you asked her, which prompted Crystal to shake her head, "well, I also only know little about using a spear. My teacher used sword so I followed his style"
"What are you saying?"
"I'm telling you we will have to stick to our old weapon, but we have different bodies right now. There will be differences in height, weight, strength and balance, so we have to get used to our bodies ASAP if we want a chance to capture that monster tomorrow," you explained.
"I... I understand..." Crystal said softly.
"Good, now give me my sword"
You traded weapons. First you tried to practice on your own. Crystal's body was only somewhat shorter than you, and the difference in weight was not that great either. The problem would be in strength as Crystal only focused her training on her arms to swing her spear, which made her leg not as strong. Meanwhile, you relied on your leg a lot to run, dodge and kick down opponents. You would have to change your fighting style. Also, with the extra weight on your chest which was nonexistent when you were a man, added with several other anatomical differences, your sense of balance was hugely overthrown. Crystal also seemed to have difficulties in getting used to your body.
A couple of hours later, you two tried mock battle. Your movements were so awkward that you were sure you would be killed quick if you faced a tough enemy. Crystal wasn't any better. You decided to stop about an hour before sun set and got back to the inn.
In the end, the result of your training was...