Since Patch 6.1, a new PvP Series begins with each of Final Fantasy XIV's major patches. Series Five brings thirty new Malmstones for players to work through, offering a combination of Trophy Crystals and new rewards.
As the name implies, progressing through the PvP Series requires participating in player-versus-player matches. Not to be confused with the Crystalline Conflict's ranked seasons, players earn Series EXP by playing any of FFXIV's PvP modes. The different modes all award Series EXP, tomestones, job EXP, and PvP-specific currencies, though the amount you receive varies based on a win or a loss.

All PVP Series Five rewards in FFXIV
Each Malmstone in a PvP Series requires increasing amounts of Series EXP, granting a reward for every five levels with Trophy Crystals in between. Here are the rewards available to Warriors of Light in PvP Series Five, along with their required Series level:
Level | Reward |
Series Level Five | Ballroom Etiquette - Defeatist Attitude (Slump) |
Series Level 10 | Palaistra Framer's Kit |
Series Level 15 | Tourmaline Weapon |
Series Level 20 | Cloud Nine Framer's Kit |
Series Level 25 | Fierce Tyrant's Attire Coffer |
You're rewarded 1,000 Trophy Crystals for every level between, which can be exchanged to the Crystal Quartermaster at The Wolves' Den Pier (X: 4.4, Y: 6.1) for even more rewards.

How you progress through the PvP Series depends on player preference. Some prefer the large-scale battles of Frontline, while others may enjoy the fast-paced Crystalline Conflict. Every method is viable, and you aren't stuck with just one.
Since the series lasts for the entirety of Patch 6.5, you'll have plenty of time to work through each Malmstone. Doing a Daily Duty: Frontline and a match of Crystalline Conflict a day will guarantee you earn all the rewards long before the series ends.