В общем, С6 это не совсем С6, а , скорее, С2.0 (если С4 == С1.4).

На самом деле все обстоит вот как:

Saga
Sagas are the set of Chronicles of Lineage II. The first time they introduced this is with the upcoming Saga 2: The Chaotic Throne which will start with the "Interlude". The first Saga was entitled "The Chaotic Chronicle" which started with the "Prelude".

Chronicles
Chronicles are large-scale updates to Lineage II done every half a year. They are free expansions to the game that every subscriber must download in the form of a patch. As the "Chronicles" advance, a new story develops. There are major game alterations in each new Chronicle, and the game balance has greatly changed in every case so far. Each chronicle also adds a great deal of new content to the game, including new skills, quests, areas and items; some chronicles also increased the level cap.

Saga 1: The Chaotic Chronicle
Chronicle 0: Open Beta Test "Prelude"
After the closed beta test ended, massive numbers of users poured in at a surprising rate when during open beta test's first day. Frequently during the beta test, especially in Japan, NPCs did not spawn correctly because of the massive number of users.

Chronicle 1: Harbingers of War
Released June 29, 2004 Chronicle 1: Harbingers of War added stirring castle sieges, new fierce monsters, items and quests, and a significantly expanded 3D world. Among the many new quests available to players is the Dragon’s Cave quest, which results in a showdown with the massive Earth Dragon, Antharas. Many of the new quests are designed to challenge higher level players, in particular. Also featured in Chronicle 1 are dozens of new weapons and skills for players to obtain. There will be clan housing, where clans can bid on clan halls through an auction system. Additionally, player and creature movement speeds were increased and new PvP arenas were added.

Chronicle 2: Age of Splendor
In Chronicle 1, when a clan successfully won a castle siege, there was not much gained from it other than reputation and pride. After Chronicle 2 was released December 8, 2004, a manor system was added. New parts of the map were added as well, such as the water city of Heine, Devastated Castle, Tower of Insolence, the castle of Innadril, the Aden Coliseum, Alligator Island, Field of Whispers, Field of Silence, and others.

Chronicle 3: Rise of Darkness
With Chronicle 3 released May 2005, came a new twist to the L2 universe called the Seven Signs. The idea behind this twist is to pit two factions (Dusk & Dawn) against one another in a competition for Seals. This competition is voluntary but not joining may hinder progress later in the game (when one is a high level player). Seals are items dropped by mobs that, when turned in, will give players Ancient Adena. Ancient Adena is another level of the Economy in L2 and allows players to purchase items they would not normally have access to.
The addition of the Seven Signs competition also brought a large number of dungeons across Aden called Catacombs and Necropolises, that only participants in the competition can access. For one week, players compete for and turn in as many seals as they can. Winners are given exclusive access to the Catacombs/Necropolis and the losing side will be locked out for one week. During this period, players can also exchange their seals for Ancient Adena. There is also a part called the Festival for parties of 6 or more. The party enters a room and kills monsters (also called mobs) until a time limit is up. This part of the Seven Signs also contributes to scoring in the Seals competition.
Other notable changes are: castle owners now have access to a fire-breathing Wyvern (Dragon) that they can fly around Aden (it should also be noted that they are very expensive to spawn and keep alive while in use); A Grade armor/weapons were added; and a subclass system was introduced that allows players to add another class to their character after level 75.

Chronicle 4: Scions of Destiny
Scions of Destiny was released on February 8, 2006. It featured expanded content in the form of new territories, enemies, summons, equipment, and a system designed to reward diligent, high level players that are victorious in a tournament in which they contend with other players in single combat. This expansion was released by NCSoft's North American counterpart on their Public Test Server on the 8th of January, 2006.

Chronicle 5: Oath of Blood
The Chronicle 5 expansion was released September 6, 2006. Clans received a makeover and the player level cap was raised to 80. New siegeable castles were added to the towns of Rune and Schuttgart. The Demonic Sword Zariche was introduced.
Clan reputation can now be earned through Clan Academy, Clan Warfare, Clan Hall Battles and Clan Quests. Clan Reputation can be used to increase the rank of the clan to unlock clan skills and items. Clans of rank 5 and higher can create academies for the purpose of training and developing clan members. Members that complete their second class transfers through the academy receive commemorative items and increases the clan's reputation. Clan members of level 5 and higher can obtain a clan title. Clans can now have a maximum of 140 players, compared to the previous 40 players; accordingly, alliances can now only have 3 clans, instead of the previous limit of 12.
Roughly 50 skills were added for levels 55+ and the function of certain skills were refined.
An extensive new crafting system was also introduced based on Life Crystals[2] farmed from raid bosses, which can be traded to NPCs for items.

Saga 2: The Chaotic Throne
Throne 0: Interlude
The name of the next Lineage 2 Saga was made public on October 12, 2006. Named "Lineage 2: The Chaotic Throne", and the first Chapter is entitled "Interlude", setting a new course for the Lineage 2 legacy. Interlude went live on Korean servers in December 2006, while on the US & EU regions, Interlude went live on April 11, 2007.
Features: Roughly 60 skills will be added, 51 of those are for levels 76+ and 9 for levels 55+. The function of certain skills will be refined.
Interlude consists of many new features, some being fortresses. Other things include masks, weapon augmentations, additional hunting zones, a new demonic weapon for PvP, and a lot more. Interlude features the 'lost island' (or new island for the players) named "Primeval Isle" where, according to Lore, the Giants used to live.

Throne 1: The Kamael
Throne 1 will include a new race, "The Kamael", it is not known yet if it will be the playable or non-playable race, as NCsoft said they will add one PC and NPC race. Throne 1 will also introduce the Fortresses and Nation Wars among others. Not much is known about the Fortresses, but the Nation Wars is a feature that will allow not only an inter-server siege and competitions but also a regional siege and competition. This expansion will also add two more countries in the world of Lineage II.