During the dark brotherhood quest I killed the Emperor and then I wondered.

What will the empire respond?

Will the empire pick its ruler?

Will the thalmor attack the Empire or install the puppet Emperor on the throne?

Pretty big spoiler dont you think? not everyone here has done that already

An even bigger spoiler:

Nothing will happen

Seriously

You get a few comments from guards and people you walk by, but that is it. Seems no one really cares, course no one seems to care that you defeated Auldin either so...

I suspect the Empire can't respond because it's a Dark Brotherhood slaying.

The Dark Brotherhood pretty much is beyond reprisals unless you can find their headquarters.

Now, if ULFRIC had ordered it, the Empire would have burned Windhelm to the ground and salted the ashes.

The Empire won't fall, though, since the Elder Council can select new Empires as far back as Uriel Septim.

If they know, that is. Dark Brotherhood assassinations tend to be untraceable, as they are professionals

I imagine they know it was the DB due to the attempt on the false emporer. Other than that, I don't believe they will be able to actualy trace it to the DB.

I imagine the Emporer has a long list of capable enemies able to do the deed.

Morag Tong is certainly one of them

Well the DB is kind of in the water closet so they need some good publicity. Slaying the Emperor would probably be good for their business.

I thought the Morag Tong was scattered and no longer existed as an organization.

You know what's really interesting? I never do the DB questline, choosing instead to kill them all (yeah, all half-dozen of them....) and I STILL get guards saying the Emperor's been assassinated. Very odd.

Titus Mede II was not long for this world.

I think that's probably a bug but I think it'll be canonical he's dead.