I saw a few build with two daggers. They speaking about passive but I don't unterstand why it's different than a sword.

Since couple of patches you'll do fine with daggers honestly, it's marginally different especially when you need to do a heavy attack for resources just use a staff on a back bar for that. If you want daggers to be swords use outfit system for the looks and look at the weapon line passives for a decision on what weapon to run beneath the "skin".

With staff you have range, which is important to avoid a lot of boss-centered AOEs. With melee weapons you have to reduce your DPS while avoiding AOEs.

taupe_agile wrote: »

I saw a few build with two daggers. They speaking about passive but I don't unterstand why it's different than a sword.

The relevant passive is called Twin Blade and Blunt, from the Dual Wield skill line. It gives you a different type of damage-boosting bonus depending on what type of one-handed weapons you have equipped. Daggers boost crit chance, swords boost weapon and spell damage, maces boost penetration, and axes boost crit damage and healing done. (The Two-Handed skill line has a similar passive called Heavy Weapons, which doesn't include a counterpart to daggers because there's no two-handed version of daggers.)

The number-crunchers who design these builds have determined that the crit chance boost from dual-wielding daggers is the most effective bonus for increasing DPS, because it helps you crit more often and that's considered the way to go these days.

As Varanis said, swords and daggers are stamina-based weapons and therefore are not typically effective for magicka builds, but in this case the Twin Blade and Blunt passives also apply to magicka-based damage so you can still benefit from the damage boosts using your magicka-based class skills. (Unfortunately, the active skills from the Dual Wield skill line are all stamina-based, so they won't be very effective on a magicka build.)

That's kind of a niche use-case for dual-wield weapons, though. Beyond that, staves are the only magicka-based weapons in the game, so most magicka DPS builds will use staves by default.

If you feel strongly about wanting to use dual blades for your character, you can put together a functional build with dual daggers (maybe with the appearance of swords using the Outfit system) and magicka morphs of class skills and skills from other sources. Consider having a staff on your back bar, since staff heavy attacks will help you restore magicka to keep your primary resource up.

taupe_agile wrote: »

Currently, I play for PvE and exploration. Pvp maybe later.

I want to play a vampire nighblade with a sword. One or two handed, I haven't chosen yet. It's an an aesthetic choice.

But all the builds I found are with an inferno staff.

Could you explain why ?
Does it really matter ?

Lots of good answers above. TLDR - its for the magika return on heavy attack and pssives (mainly 10% extra single target damage from inferno staff).

That said, dual wield and even 2h are perfectly viable. Dual daggers give you extra crit, while dual swords give you 284 extra spell damage.

I actually run 2h swords on both my magblade and my magdk. Mainly because I just prefer the look (my magblade is dressed up like a little samurai and wields a katana) but I actually find it gives me really good dps. Between the extra base spell damage 2h swords give you and the heavy weapons passive, a two hander can give you 5 or 600 extra spell damage. Plus if gives the magdk access to a gap closer I think he desperately needs.

And, tbh, if you're playing for pve and exploration, it really doesn't matter. Play how you want I have a lot of fun with my magblade, he jumps in with lotus fan, runs concealed weapon as his spammable, uses impale as an execute, and also front bars mass hysteria and shadow to pop in and out of combat, fear enemies and generally cause havoc. The BB is then a maelstrom staff with your usual magika stuff - unstable wall, twisting path, sap essence for major sorcery etc