Letter from the Producer Live Part VI wrote:
Q: Please give us more details on PvP.
A: I'm not sure how knowledgeable most people are about PvP, especially in the JP community, but the coliseum that we're planning to implement at launch is something like...a gathering place for the world's strongest warriors. When a PvP battle starts, you'll see four players from the opposing team on the other side. Once the signal is given, the battle starts. Now, if I was a black mage, I'd obviously focus on casting magic from a far while trying to keep my distance, since I'd be slaughtered in close combat. I might also hide behind pillars or other obstructions while attacking to prevent others from targeting me.
Of course, I'm sure opposing warriors and paladins would attack me first because of my low defense, so I would probably try to cast sleep or repose to take them out of the fight for a short while. Depending on your role and the situation, you'll want to fight with a different style. And, as I mentioned in the previous live letter, you can use the environment to your advantage. These matches will be balanced around 4 vs. 4. Hopefully everyone can try it out and go from there.
That's the general idea behind PvP. Of course, there will be situations where melee characters try to ensnare casters, or think of ways to prevent the opposing player from running away with sprint. Oh, and you'll be able to restore TP by using potions. I could go on and on about it. Anyway, you’ll receive points when you win a match.
And when you gain a certain amount of points, your PvP rank will go up. As you gain ranks in PVP, you'll receive a different type of points. These particular points can be used to obtain weapon skills, for example. PvP players can create certain builds by using these points. These points can also be used to purchase the PvP gear I introduced last time.
*Artwork of PvP gear is shown in the video.
So essentially, your goal would be to gain points through matches to obtain PVP skills, passive abilities, and gear to grow stronger. You can even buy—well, I might get yelled at by the Battle team for saying this but...
For example, you'll be able to purchase this one paladin PVP ability, and its effect changes depending on what grand company you've joined.
Based on this, it seems like anything earned in PvP will, for now, stay in PvP. This is speculation, of course, since no one has participated in it yet. I would expect it to be/stay that way for quite some time though, due to the almost exclusively PvE nature of the FF series.