I like both, but how do you justify it RP wise?

I mean, after doing the DB quest, Mercer will know you're a member for instance.

If I remember it correctly, and I put this into a spoiler:

Well personally yes, and as a Shadowscale Argonian Vampire his justification for serving the TG is to honor the Night Mother who is connected to Sithis directly by supposidley being his wife (or was), Reason: she used to be a member of the thieves guild, explanation below, and so by honoring where the Night Mother began her illustrious career i am honoring her and sithis as they are wed (or is beleived thats the case) i also perform assinations while im in the DB though not for there jobs as that i beleive would insult the integeraty of the Night Mother.

I will honor anything connected to Sithis so he can fully see my Devotion, although i will not let it or anyone control who i am or what i do, if i disagree with something i well not hesitate to refuse.

His RP is complicated and has been going since morrowind, il lwrite you the whole thing if you like though im not at home at the moment so i cant copy / Paste it haha.

I am in both and Companions and Mage as well. The guilds seem to operate in different universes. Their missions and accomplishments never seem to intersect. For example, in one guild, you kill a well place political figure but that doesn't seem to affect any other guild or any NPC anywhere in the game.

No real direct conflict between the guilds (or any other for that matter) so I never saw a need to justify it through some roundabout reasoning. Also, what sdack said.

By the way, in before the "lol nothing you do affects the game" crowd comes pouring in.

he said RP wise...so you kinda need a reason.

Some quest lines have an effect on each other. Get far enough in the Imperial quest line and you can use your influence to free a prisoner out of jail needed for the Companions quest line.

I like stealing stuff and I like murdering NPCs for their stuff. So, it works for me.

Really? Damn, if I had known that I wouldn't of slaughtered the Thalmor.

If you're going to do both, you must remember to not kill whilst stealing. Getting your hands dirty when not necessary results in undue attention and wouldn't befit an agent of Sithis.

I thought I wrote that I don't kill enduring tg jobs? Well if not I was meant to write it lol

They're definitely intertwined. Evidence: they guy in the TG helps with the new place later. Explanation:

Also he knows several members by name and past relationship. It is pretty clear they are neutral to one another and have business dealings.

RP wise I don't have an issue justifying it. My character will do anything for a profit. Heist/Numbers/etc. jobs for TG, and murders for DB. So long as she gets paid, she's happy.

I have two characters on which I joined both of them. In both cases, I started with the Thieves' Guild, and since I was quite an aggressive thief that didn't mind some killing if it earns me some loot, I decided to join the DB too.

I joined the DB first, as their gear helps more with sneaking than the TG attire does. RP-wise, my Orc will do whatever benefits him and ally with whoever benefits him.

Astrid suggests having thives guild connections to handle any murder related bounties. There's your RP option right threre.

Yeah, I thought I had remembered one of the members of one of the groups referencing the other.

From memory, Mercer also makes a comment about an arrangement with the DB whereby the two guilds won't step on each others toes.

i did all. companion , dark brotherhood and thieves...

spoiler * if you complete thieves first.. then you do dark brotherhood.. there will be a part where by astrik will ask you to look for drevan to evaluate the price/value of some jewel.. *sorry forgot his name.. they seem to have an affair.. haha.. then when you speak with that d guy.. he will comment... " you made quite a lot of friends.."

Yep. Forgot about that one too. I did them both pretty much in conjunction, but had advanced DB farther at that point and got the same dialogue from Delvin.

I just did the DB quests first, and then the TG.

Since this character is only doing the DB because a seer told him that would let him (kill someone important), and the other to (get a particular artifact), he's basically using both guilds, so justifying what they think of each other is not even on the map.

In fact, out of all the factions across Skyrim, these two are the ones that fit together and clash less than any other. When I mean clash, I actually mean by intentional purposes, not that any one faction in Skyrim gives a flying skeever what the other thinks or does.

They do that a lot. And since the TG is a tad bit more unethical than in Oblivion, the collusion between them and the DB is not so far off the mark. They are both pretty bad people.

I did the Thieves guild quests first and once i became guild master joined the DB. I just had Delvin take a look at the jewel he's supposed to assess, and his dialougue was well integaretd; he seemed to realize I was involved in both and seemed to be cool with it.