I know most people get hung up on the whole Emperor part. But I'm more puzzled from a different angle: how can General Tullius and Legate Rikke not know you're the one that killed Vittoria Vici? It's almost certain you'd get a bounty in the process, and since Castle Dour is pretty much the law enforcement center for Haafingar Hold, there's no way the military governor could not be aware you're the assassin. And I'd think Tullius would be aware of the shenanigans with the Penitus Oculatus later on.

Now, I don't claim to know the policies of the Fourth Era legion, but I should think Legionnaires assassinating a prominent East Empire Company executive at her public wedding (and later killing Penitus Oculatus agents and the Emperor's body double) is frowned upon. That would make "Bound Until Death" a permanent cut-off point for your tenure in the Legion. So I guess what I'm asking is....why didn't Bethesda put more severe and logical consequences for doing the Dark Brotherhood quests?

Well you can do it stealthily and in a disguise. Not to mention you get some help in the process.

Hmm... I just started DB quests myself but I can tell you this for sure. General Tullius won't know anything of the sort, since he's already dead in my game. And no, I don't recall how that happened either, it must have been from some time ago.

I no longer do the Dark Brotherhood and the Legion. Makes no sense.

Two words and this is going to be a shocker "Video Games." I remember the days of Morrowind where if you joined a guild that didn't like another guild you would get a bad reputation with all those guild members, and that guild would be locked for you. But now you can do every guild for the sake of "Well the game needs to be fun or no one will buy it." It is sad to say but the age of the hardcoe RPG gamer is dead and gone, developers won't make a game specified for the less then 20% of there player base now even though that 20% was there 100% 10 years ago and without them they would of never gotten there feet off the ground so to speak.

Bad game design

/thread

Well a loyal imperial would leave the brotherhood as soon as they realized the emperorr was the target.

That being said you can kill the bride without a bounty. But the emperor, including the fake one... yeah I'm pretty sure the imperials know it was you.

You don't do DB at all?

That's why if I wanted to do the Civil War AND the Dark Brotherhood, I do the following:

#1- Join the Stormcloaks. What I do in the DB weakens the Empire.

#2- Do the DB first, then Legion to roleplay a character that suddenly has a change of heart, though to be honest, it doesn't make sense because why would Tullius allow someone who pretty much cleaved through the top guards and at least two members of the Imperial family join his ranks? He ought to have that person run through on sight.

#3- Do the Legion first, then have your character decide to betray them for whatever reason (he/she got disillusioned, etc.)

Regarding #2/#3, my character assassinates the Emperor to allow himself a better opportunity to seize power in Cyrodiil. He's created a power vacuum, he's the hero who vanquished Ulfric Stormcloak and saved Skyrim, he can use the Thu'um and commands an army of dragons. Flying into the Imperial City on Odahviing seems to be the next logical step to become the heir apparent of the Empire.

@OP, It's pretty easy to not get a bounty during this mission.

Option 2.