Never played Morrowind and having fun. But I have just killed an assassin (early on) and the Armor seems out of place. Is this planned? It is quite a set of Armor.

In the original version of the game, without expansions, there were no such assassins; they were added by the Tribunal expansion, which was not designed for new characters.

From what I have read, on the Xbox version, even with Tribunal installed they don't appear until you reach a certain level (something like 5 or 6); for whatever reason, however, they appear right away on the PC version. Many consider the armor to be a bit too good for when you can first get it, and some players may prefer to play without the expansion at first (installing it later when ready), or use a mod that delays the start of the expansion.

It's entirely up to you. You can wear it, sell it, throw it away, put one aside for emergency purposes, ... The first two options make the game a lot easier, at least on the early levels. And the assassins return regularly.
There are mods preventing them from appearing, simply search the internet for "Tribunal delayed" or so.
I myself use one of these mods and play the whole game without the assassins.

Thanks.
Sold it. stop me from having to become a farmer to pay for my lessons.
Thanks.
For all the good armor he was too easy to kill. Strange mod.

To my understanding, these assassins scale with your level, and at higher levels, they can actually be quite dangerous.

I believe that you can stop further attacks by telling a guard about the incident. Alternatively, you could just play without Tribunal enabled, and only enable it when you are ready to play the expansion.

(One thing to note, however, is that if you don't enable Tribunal, or if you disable the assassins (preventing Tribunal from starting), you won't be able to get the Fortify Skill effect; the only other source is in the island added by Bloodmoon. Then again, some might consider that effect (or at least certain uses of it) to be too powerful.)

Another alternative - you can install a mod which delays the assassins;

https://www.nexusmods.com/morrowind/mods/14891/

Might be a bit late now but worth remembering for a future play through :)

Thanks one and all.
The next assassin was tougher. So I think I will keep it in.
Not really the same but this game does remind me of U7.

I haven't played Morrowind without Tribunal enabled for ages, but if I'm not mistaken, disabling Tribunal also means disabling the revised Journal (or was this added to the base game, too, later?).

Good Game But started over.
I did not realize how easy money from the Shadow armor could break the game (training)
I looked at the Nexus site but I have had a bad experience with Mods. I am not saying it's a bad site. Looks professional. but once burned.
This time Breton and more magic oriented. We'll see.
I'll just ignore the Assassin dead (if they lose).

I remember doing mods around this.

Start the quest automatically (basically only one assassin attacks you)
http://mw.modhistory.com/download-95-6715

Delaying the attacks until you get a bit of reputation:
http://mw.modhistory.com/download-95-6670

Well I trapped an assassin in a basement which I won't likely revisit for some time.
I figured maybe if I get one still active, it will keep others from being sent at me.
We will see. If it works I will take my time in ending the assaults.