You would think so, but the defensive capabilities of this class far outweigh those of most Assassins. First of all there's Histskin which can more or less keep you alive no matter what's getting thrown at you. Then, even though youve only got armored gauntlets and boots, they're nothing to scoff at when supplemented by Ebony Smithing and 5/5 Juggernaut, especially when coupled with a Flesh Spell. Can't forget the emphasis on the Block skill, either, which allows you to absolutely control battles and mitigate damage. And finally, enemies aren't much of a threat when you're holding their weapons or they can't find you to begin with, which are the two things this build most excels at. It's nice to play as an Assassin with some defensive capabilities who can therefore be more methodical though, and doesn't have to worry about maximizing his damage output to prevent getting whooped.

actually it still does fit. The backstory event took place before skyrim, so he simply dropped the blade

First I'm seeing it too lol. And like my friend here said, he had a Shadowscale build already that he courageously requested to have deleted, throwing away quite a few likes out of sheer confidence in what we've done together.

Anyway, I fixed it.

In the new story it says that he used his enemies weapons to kill them. That's what he is good at, so that's what he does.

I provided the link in my comments - just click on it to find 'where it is hiding' (dated May 21st).  (The site has a search feature - far top right)

All brilliant role-playing ideas and I personally like to leave a lot up to the individual player. Really, it began as more of a gameplay choice inspired by one of Emer's special moves from the original build that I felt would be an interesting concept to base a unique assassin around.

For me though, it's more a culmination of the Shadowscale's abilities. Any assassin starting out would certainly need a blade of his own to take down his targets, but how good would you have to be to have the confidence to walk around without a weapon and know you'll find something somewhere to kill someone with? For my own Shadowscale playthrough, it became as much a role-play choice as it was a gameplay gimmick, one that really helped to make me feel like I was embodying the type of trained killer who didn't need to carry a weapon because he could turn anything into one.

At one point very early on I snuck up on two bandits and grabbed the pickaxe laying next to them to slaughter them with. It was one of my all-time favorite Skyrim moments and made me feel more like a true assassin than any throat-slit has.

They're buried in the void somewhere ... I used the aforementioned search feature to find it, because I remember seeing it before (thought honestly, I think it was Emer's that I remember reading from before.)

There's a few places. Off the top of my head, the Winterhold college (obviously) and Wylandriah at Mistveil Keep should sell it too.