It's probably mod-related, hence this section, but I'm not sure. Specifically, it's The Silence Has Been Broken. I've killed all previous quest targets, most recently Lurbuk and Hern. Upon returning to the Sanctuary, Astrid gives me the speech which should start TSHSB, the "main" questline. But it doesn't, Astrid will only give me the same speech, and talking to Nazir to turn in the two assassinations only results in him telling me to see Astrid.

I'm at my wit's end here. I've tried everything on both wikis, but neither of them, nor any other discussions anywhere online seem to have this issue. As far as I can tell there's no way to add an individual quest via console, and setstage DB04a (supposedly the id for the quest in question) does nothing, with any of the stage numbers. getstage db04a shows 0.0 which I have to assume means the quest isn't even there. It's like it's disappeared from the game, and taken the rest of the DBh questline with it.

I've talked to Amaund Motierre directly, and he acts like he's supposed to, except when he says "Rexus, the items!" Rexus just stands there. He just grunts at me. Motierre will start the speech over again like it's all new. I've added the key items in via console, and nothing, they even have weight so they're not quest items. Devlin Mallory just gives the usual dialogue too.

I should mention that this is the third character over the last few months I've tried this with, from scratch, and all met the same dead end. (Well technically it's the same character, I'm an RPer, but anyway.) At first I thought it was Live Another Life, but even without that, same result. 95% of my mods are purely cosmetic, but I did have Requiem at one point, and I can tell by some of the mechanics that some of its scripts are present, mining for example, but surely that mod didn't kill the Dark Brotherhood? I've seen no evidence of it online. (And yes, I've tried a script cleaner too, which found nothing wrong.)

Is there anything else anyone can think of to try? The rest of the game runs smoothly, no bugs at all besides well-known ones, every other quest is delivered no problem. So I turn to you in desperation. Am I simply doomed to performing a completely clean installation? I shudder at having to reinstall all those mods.