PvP is typically a mano-a-mano situation where you fight another player. Depending on the way you fight, you may get different rewards: from Tokens of Spite to upgrade materials.

It’s fun! It tests your ability to deal with various interesting challenges against players that react according to your actions: if you’re a PvE fan you can consider this a mini-boss run, similar to Dark Chasm of Old. Plus, it's an opportunity to try out new and fun builds without risking much.

There are multiple ways to engage in PvP.
For non-covenant members the best way to do this is to touch red summon signs or dragon eyes: this will summon people into your world to fight against. Another way would be to find/farm Cracked Red Eye Orbs and invade people through those.

There are also multiple PvP covenants in Dark Souls II:

Bloodbros level up their covenant allegiance by dueling on arenas in located in Undead Purgatory. After they win a duel, they receive a Cracked Red Eye Orb, which can be used to invade others throughout the game. This covenant is your choice is you want to get your hands deep and dirty into PvP: arena is free to attend, Tokens of Spite you get from winning invasions increase the chance of people invading you. Generally considered a late-game PvP covenant. To join it, you need to talk to Titchy Gren in Undead Purgatory after having defeated the Executioner Chariot boss. Note: you need to have at least one Token of Spite in your inventory to join this covenant.

Way of the Blue (also known as Covenant of the Meek) allows you to summon help against invaders in form of Blue Sentinels. Joinable through Saulden, the Crestfallen warrior near the death count statue in Majula.

Blue Sentinels, on the other hand, are more of a “passive aggressive” covenant. Their main goal is to assist Way of the Blue players and to punish sinners. Sin can be acquired through successful red invasions or by killing NPCs. They have their dedicated PvP arena as well, however they need Tokens of Fidelity to enter. They are the only covenant which can use Cracked Blue Eye Orbs, in addition to Cracked Red Eye Orbs, to invade people. Rewards for covenant progression are powerful miracles, useful both in PvP and PvE. To join talk to Targray in Cathedral of Blue while having at least one Token of Fidelity in your inventory. Blueberry covenant is good if you want to help people, while still PvPing. Plus, it’s accessible within the first hour of play - a good way to set start in your PvP journey.

Covenant similar to Forest Hunter covenant in the first Dark Souls. You protect boundaries of Belfry Luna and Belfry Sol areas by invading as a Grey Spirit. Honestly, one of the most useful covenants, as you get Titanite Chunks, the most needed upgrade material in the game. PvP here, however, can be slightly unfair: you often fight with other spirits against a single person. This covenant is a great introduction to the way PvP works, but it falls of lategame - people with greater soul levels/soul memory just don’t visit those areas, apart from ones specifically looking for PvP matches there. Engage in protection through Belfry Guard guy near the entrance to any of Belfry areas.

Covenant spiritually similar to Bell Keepers. Your main goal is to "protect the king!" by not allowing invadees to reach a fog wall usingany means possible. You summon people into your world and challange them for a run-through of the trap-filled maze and a duel at the end. This is both a PvP and a PvE covenant, as it's possible (and sometimes much easier) to rank it up by farming rats in Grave of Saints.

Is this covenant for you? Well... Here are three questions: 1. Do you like hurting other people? Do you like constantly fighting higher-level opponents? 2. Do you have 10+ Lockstones? 3. Are you ready to somehow stop the "Zero Sh*ts Given" guy who just ran through all the traps and is now entering a fog wall? If your answer is "yes" for two or more of those questions, try it out, you may like it. At the very least, being a Ratbro gives you a pretty unique and interesting perspective on PvP interactions. One piece of advice though: Doors of Pharros > Grave of Saints.
Joinable through Rat King in Grave of Saints/Doors of Pharros after beating area bosses.

This is probably the last covenant most players encounter on NG. Dragonbros are obsessed with getting dragon scales, which would be used to transform their body into dragonoid shapes. You’re being summoned through the use of a Dragon Eye, in a way similar to using a Red Sign Soapstone. From what I’ve encountered, Dragonbros are more-or-less old Dark Souls I guard, always respecting PvP etiquette and being actually OK at PvPing. Overall, a really fun covenant if you want to do some of the more quirky stuff with your character. I would recommend progressing this covenant to lvl2, so you can obtain Dragon Head and Dragon Torso stones, and joining a different PvP covenant later.

Whenever you want! Generally, though, I’d recommend starting once you get your favourite weapon to +10, as by that point in a game you’re familiar with both mechanics of Dark Souls II, as well as how your weapon works.

To answer the second question, there are multiple tiers of PvP. Invasions happen throughout all of the game, in most sl/sm ranges. Blue/red arenas are also somewhat level-independant, you’ll most likely have no problems finding sparring partners. However, most players consider that “real PvP” starts around SL150 on New Game Plus: which is true to a certain extent, as you can get certain PvP-specific rings only on NG+ (or by using Bonfire Ascetics).

Here I listed the most popular locations for PvP:

1. Red and Blue arenas.
Kneel before statues in Undead Purgatory/Cathedral of Blue to start "matchmaking". Game will automatically find a partner for you, you just have to wait. Arenas are generally balanced, however they may get old for you - so here are other "unconvetional" PvP arenas!



2. Heide's Tower of Flame. Closest bonfire: Tower of Flame
Favourite place of gankers. If you invade here, be prepared to face multiple opponents at once without any real backup. In gank situations, PvP etiquette goes to sh*t: feel free to heal up, push them off the ledge, etc - you are at a disadvantage here.



3. Huntsman's Corpse. Closest bonfire: Bridge Approach
Babby's First Invasion Location. Most of PvP happens on either the smal bridge to the right of the bonfire or on the elevated area on your way to Executioner Chariot. New Game PvP here is mostly new-er players, be wary of unintentional ganks however.



4. Iron keep. Closest Bonfire: Threshhold Bridge

My personal favourite "unconventional arena". You can encounter a lot of interesting stuff around here: from "fight clubs" where the host summons multiple spirits and they fight among each other to Dragonbro gatherings with non-stop summoning action. Overall, a very fun place to fight at, plus it's spiced up by having an environmental hazard people can be pushed into - it's no fun swimming in lava!



5. Doors of Pharros. Closest bonfire: Gyrm's Respite
Unless you feel lucky/sadistic on any given day, avoid this place like it's plagued. One of the primary gathering places for Rat King Covenant: it's filled with traps, daemonic contraptions and jerkface enemies. However, should you decide to venture into this madness, remember to bring some lightning with you: the floor is flooded, which lowers lightning resistance of all enemies (including players) in that area.



6. Dragon Shrine. Closest bonfire: Shrine Entrance
A late-game PvP arena. Not a lot of people invade here, but there are lots of summon signs/dragon eyes on the ground. Nothing specifically interesting going on here, but the level layour itself may make for an interesting PvP experience.



7. Pursuer Arena (NG+). Closest bonfire: Forest of Fallen Giants - Cardinal Tower
Pre-NG+ I haven't seen much here in terms of summon signs, but in NG+ this place serves as a very early PvP arena. Plain Ol' rectangular arena, with a lot of space to roll and cast spells.

Image taken from my other guide, enjoy!

Thank you for reading this guide, hopefully you players out there found it helpful. And remember: respect the etiquette to get most out of your PvP experience!