As we all know Lineage II has a huge variety of classes. To be more specific, I'll say that Lineage II in total has an incredible amount of 34. So today we'll try to understand some basic class concepts and what do they exactly do in parties (Party - that's what groups are called in Lineage II). I'll be using the names of the second profession, because those are the most common and the largest number of people use/know them.
Lineage II stats influence
In order to speak about the classes in-depth we have to understand some basic principles of stats in Lineage II. This mechanism can be quite difficult at first, but when you understand it, it's fine.
As we see there is a separate bar, in character status window, called Stats. What do they do? They are one of the biggest factors which determines your combat stats like p.atk, p.def and so on. I'll try to explain, what those 6 stats are exactly doing:
To sum up, the first three attributes: STR, CON, DEX are mostly used by fighters and the last ones INT, WIT, MEN - by mages. One more thing. When you create a new character in Lineage II,you have to choose a specific race and later, you need to choose what type of character you want to be: Fighter or Mystic. Remember, both character types possess DIFFERENT set of stats. As I'm writing about the tanks, I'll use only fighter's stats.
Tanks - General Approach
The role of tanks in the party is to take all the damage caused by the mobs (mobs = monsters), using skills like hate or aura of hate which turns the attention of the monsters to the tank. It's not everything they can do. They can increase their defense at will in order to defeat their opponents. The increase in defense, using the mentioned skill, is huge. However, the majority of them doesn't possess strong attack skills. As a result, killing the monster alone is very slow and tiring, because you deal a smaller amount of damage. As soon as we get deeper into it, you'll understand the main differences of playing style between them and you'll be able to choose what kind of tank you exactly want.
Stats: INT 21, STR 40, CON 43, MEN 25, DEX 30, WIT 11
Class tree: Human fighter -->Human Knight-->Dark Avenger--->Hell Knight
This class is one of the most beloved tanks ever. It has quite a good balance of CON, STR, DEX, so it's very versatile and universal. This tank has the best possibilities for soloing in PvE, because of its ability to summon the dark panther to help DA in combat. Yes, it's the only tank class who can summon a pet or a similar thing to help him. So, despite the fact that DA himself is quite bad at damage dealing, his partner, the dark panther, fully covers this weakness. However, as a DA you have to be very careful and always spam hate, while she's doing the damage, because otherwise, mobs will target and kill her quite easily. Another very nice feature of the DA, is that it has some aura which helps him to reflect damage. However, that's not all he's got. He still has a self-buff for raising M.def. Another very good skill is Shield Stun which has the biggest stunning rate that's critical in both PvP and PvE. Those and other skills, make him extraordinarily tough in PvP. You have to remember that in 1v1 PvP, he'll always have an advantage especially against archers. Why? That's because of his ability to hold opponents. Of course, the other tanks have hold as well, but other tanks doesn't have summons. That set of skills makes DA even more versatile, mobile tank. That's why he and paladin (another human tank, which I'll describe later) are the #1 preference of clans.
I don't have any particular recommendations concerning the equipment, because it depends on your role. Of course, it's a must to have a sword/blunt with health special ability. Because tanks are meatshields and HP are very very important. Another suggestion would be taking an armor set with +CON stat bonuses. It makes HP even bigger. This would be good for the raid group, but on the other hand, sacrificing STR and DEX attribute for CON for a solo pve person can't be considered as a very good idea.