OK, so we're nearing the end of P2, and I have a few questions... I have only briefly scanned through P3, and it looks like - much like H3 and P1 - it's almost unrelated to the overarching plot of the adventure path. Would that be a fair assessment? If so, what sorts of connections have you used?
Anyway, knowing my players, I wouldn't be at all surprised if they end up holding on to Nightbringer. (And heck, the writeup seems to assume it's possible.) The sword doesn't show up at all in P3 that I can see. And while the text hints at its having a role later in the series, I've learned that this sort of promise is usually either complete BS or a half-truth, at best. What would the ramifications of this be, on later adventures?
Thanks!
-O
P3 isn't strongly tied to P1, but, to me, it's fairly strongly tied to P2, and the rest of the series. It also has strong ties with H1.
The dragon statue with gem in Zirithian's lair
could be Urishtar (and I would assume that it is).
You kill one aspiring little priest of Orcus in H1.
You kill an aspiring exarch of Orcus in P2.
You face a "self-proclaimed" exarch of Orcus in the E series (Elder Arantham).
The plans to unseat the Raven Queen that show up in the E series are related to Urishtar's dreams about "devouring a world of souls to unseat the goddess of Death".
The dreams which impel Urishtar to take over the fortress and devour the souls drawn into the vortex are sent by Orcus, who has been behind all of the events of H1.
What I did, to tie them all a little bit closer together:
Kalarel, from H1, shows back up in undead form as the Ghoul Priest of Orcus in P2. This further emphasizes that Orcus had three potential Exarchs (Kalarel, Zirithian, and Arantham), so, by the PCs eliminating some of them, they free up Arantham to claim the spot himself.
The dead hero that they are trying to enable to be raised (Jothan Ironspell) could be replaced entirely by Etheran (the Baron of Therund's son, whose head the PCs find in a sack in P1).
Instead, I established that the Barony of Therund had been prosecuting a death cult inside its borders, only to find that they had links to some heretical drow. Etheran and Bax and the other heroes mentioned in P2 had followed those drow into the Trollhaunt Swamps. Those drow are the drow working with Skalmad, the Troll King in P1, and also, the drow working against Matron Ulrvrain in P2. Thus, Jothan Ironspell is a hero killed fighting off the drow heretics who were sworn to Orcus.
Skalmad's troll shaman worships Torog. There are troglodytes in P1 as well. There are also mentions of Troglodytes and Torog worship in P3 (the trogs revere the crawler as an avatar of Torog).
Those troglodytes have also convinced the Cyclopes present that the Carrion Crawler is an avatar of Torog. Why are there Cyclopes present in the Underdark? Hey, these are some of the Cyclopes which were allied with Skalmad in the Feywild, way back in P1!
Vecna shows up in H2. He also shows up in H3. Vecna starts coming back into the picture in the E series as well (Heck, I have a PC who is flirting with following Vecna, he's so curious!).
Lolth is opposed to Orcus (as most demon lords/evil gods are opposed to each other). It seems perfectly in character for the goddess of treachery and deceit to manipulate Heroes (who are presumably opposed to her too) to fight Orcus's machinations in P2. No matter who wins, one of Lolth's enemies is dead!
The pyramid in H3 also ties back to the black ziggurat in P3. In fact, my group was worried that it was the same place! Instead, I look at those as both being mysteriously tied to Timeseus (the primordial in the E series), as they are both composed of supernatural black stone.
Nimozan the Green (from Fallcrest) is a scholar of Orcus. Together with Valthrun the Prescient, who is a scholar of the Analects of Tzunk, and the sage (forgot his name, may have made it up) in Therund, he has been able to tie the destiny of the PCs strongly together with the fate of Orcus.
The "creature" in the Temple in H1 shows up again (though not admittedly named as such), from the "other side" in the E series too. First you see it through a restraining black membrane, then, when you are a mighty hero, you face it in the Elemental Chaos.
That's just all stuff I added or modified to keep all of it tied together in my mind (and in the mind of my group). I don't think that you need a lockstep plot leading from H1 to E3, and I think the modules would feel more forced and "railroady" if you had that. Instead, there are some linkages that are definitely plot related, and others that just repeat certain themes and motifs.
In addition, the modules really can't be too strongly linked in plot, or they would be of little use for people to pick up individually.
