"Whatever they brought, it won't be enough." Legion Commander Guide

Blink Dagger is so much better for legion than shadow blade.

The main idea with legion is to use Press the Attack, Blink in and then Duel. With shadow blade you can't use Press the Attack because in the time it takes you to use it a good player should be able to get away from you.

When I play legion I rush Blink Dagger as soon as possible. My typical item progression would be:
Power Treads
Blink Dagger
Blade Mail - not absolutely necessary, but means you can kill bigger fish with your duel.
Desolator
Black King Bar - if needed. Can get it earlier.
Assault Cuirass - best item on Legion without a doubt.

after that you can think about bashers and crits.

http://dota2.gamepedia.com/Mute Useful link to know what's muted/doomed/silenced by Duel and what isn't.

I would definitely not count Crystalys and Daedalus core but if you have to carry then it might be worth picking up eventually since you're not always dueling.

Instead consider Mjollnir as it's a good pick for any right clicker plus that it works while dueling.

Abyssal is a fair pick however it shouldn't enter your inventory before the very late game, you have lock-down already, it shouldn't be a priority and the stun proc doesn't work while dueling.

Desolator is fine however if you don't pick up any strength items earlier you might end up squishier than you'd like which is dangerous while dueling. An armlet early on is almost always worth picking up and do consider an earlier BKB if the enemy team sports a lot of nuke as they (if they have any wisdom at all) target you if you duel.

Blink Dagger could be an alternative to shadowblade, it depends on the game, I'd say if your team has no other great initiation it's better, blink would also be better if your team is already sporting some sort of invis as the enemy are already prone to get detection. A tool for initiating isn't always needed though since LC has a very nice base speed along with Overwhelming Odds she can pretty much just run up to most heroes and duel them, and if someone else on your team can start a fight decently it might also not be needed. Highly situational.

Consider getting a Medallion instead of a basi ring too, it should get you a decent amount of mana regen and if you activate it before dueling it can help quite a lot.

Sorry for the wall of text :P

Even without the crit procs I take it because of the additional damage that it gives me and it helps when not dueling as you simply crush your opponent under the weight of your blow after some successful Duel kills. Basher gives us some amazing stats which make us tankier coupled with the activated which helps set us up for a duel. It can also be used to help keep a Support locked down for longer since they will be dueling to start and then hit with a CC

I've read that daedalus and skull basher do not work while dueling. Is it right? in that case, would you still consider them in your build? cheers