A new setting makes it only natural to introduce new cultures as well, or even new player races - this is at its best if the "unlocking" of these options is the clear result of PC action in the first arc. At the same time, player actions might very well remove options from play, or entirely transform a player race into something new and strange. As a general principle, I have to recommend dynamism over stasis, but anyone who has watched a long-running TV series knows that big changes to a property signal both sharks in the water. Develop a deep understanding of the themes that kept players engaged in the first arc, and keep the new material true to those themes.
The wonderful thing about setting continuity, though, is that it's more intricate than anything you could have written prior to the start of the first arc, and it has objective reality for your playerbase. I talk a lot about Historical Events in DtD as ways for characters to hook into campaign backstory, strengthening connections to PCs and NPCs. Several years of on-screen campaign history would just about do the trick, wouldn't you say? (Make a summary of those major campaign events available on your website, so that players completely new to your gaming community can do the same. Experienced players bringing in new characters already have an easier time getting hooked into things than a newbie.)
Think back to the years that you poured into creating mysteries and compelling conflicts in the setting of the first arc (since I take it for granted now that there will be a setting change). Another major challenge of the second arc is that you're either writing that setting in parallel with the last season or two of your first arc (while you're already slammed with ramping up to the finale) or you're pounding it out in the half-year-or-so between the end of the first arc and the start of the second. I generally don't see games wait more than half a year between arcs, because the longer they wait, the more players find other commitments or move on to other games. It makes gamers sound like a terribly fickle breed, and to a certain extent we are. It's just that it gets harder to remember why you loved that game, especially when the conflicts you cared about
did reach a satisfying conclusion. A new multi-year campaign is a big commitment for the players too.
Mechanical Challenges
If you were ever going to make sweeping rules changes or introduce big rules concepts (new schools of magic, for example, are a great way to give the new arc mysteries to explore!), the arc transition point is the time to do it. If you can make those changes part of some kind of Realms-shaking Event (trademark held by Forgotten Realms), it's a damn fine climax for the first arc leading to a brave new world in the second.
Most of the huge mechanical challenges of the arc closer I've mentioned above. The divergent build totals have probably discouraged the introduction of new characters, especially in the area of new recruitment to the game, and the simple truth of
any community is that churn is never zero. The best-case scenario is that the last season of the first arc is strong on recruitment to the ranks of the NPCs, because they're waiting for the start of the new arc to jump the fence. (This is also a good recruitment pool for new Plot committee members, of course.)
Since we're talking about the moment of greatest
tension in the campaign's run, the threat of death is higher in each combat than it has ever been before. In CI/Ro3 games, this probably means more instant-death effects are getting thrown around than ever before. (It was certainly in one of the arc-finale events of KG 1 that I died from charging into a
hail of Rend Spirit spells...) This isn't so much a problem in search of solution as it is an observation on common threads from one finale to another. (Do make sure you keep the challenges
remotely winnable, though.) If you have godawful things on your Effect List that you've just been waiting to do to players, let's face it, you're running out of time. I'll just post the Wildlands South
checklist disclaimer here for posterity:
The Wildlands Campaign Committee takes no responsibility, stated or implied, for the ensured survival of any Wildlands character. We are not responsible for any effects incurred to a character during a Wildlands event, including but not limited to: diseases, poisoned blood, plagues, insanity, withered or devoured limbs, scars, magical immolation, electrocution, temporal displacement, frostbite, acid burns, parasitic infestation, lingering curses, weakness from spells or alchemy, mechanical "enhancements," wounds incurred from blunt or sharp weapons, berserk rages, transformation into lower life forms, premature aging, disintegration, build or level loss, metamorphosis into a chaos corrupted bug, necromantic spiritwracking, obliteration, or Total Entropic Annihilation.
In conclusion on all of these points, running an arc finale and topping your previous successes are a major challenge, and Eclipse rose to the occasion. The arc transition is a delicate time, as the broader narrative returns to a new round of exposition, but individual character and plotline narratives (to coin a term, micro-narratives) may be in any of Freytag's stages. In the grand scheme of LARPing, I think it's fair to say that more games
don't follow arc format than
do, and even for those that do, arc transition is a once-in-a-career occurrence for most Plot members, so most people come to the challenge without specific prior experience. A lot of the traditional lessons of good GMing don't apply to arc transition: "Never take away the PCs' toys," for example, only applies if that character
isn't "compensated" with a strong sense of narrative resolution and personal glory. The guidelines of
narrative can start to trump the guidelines of game-running, as the latter doesn't have independent rules addressing finality, only perpetual continuation.