They´re the most extensive of the weapon cathegories, including 6 artifacts (base game, 1 extra in KOTN and SI each) as well as cutlasses and (one handed)katanas.
There might be some confusin here as to what qualifies as a long sword, as some of the weapons in this cathegory are visually the same length as some shortswords in the game the Debaser for example is almost the same length as Chillrend, however one is a longsword and the other a shortsword.
What makes a weapon a longsword in this instance is it being a one handed weapon, using the blade skill, with a reach of 1 and a speed of 1, as the game data shows.
(Data taken from UESP)
Therefore, weapons that only fit some of the cirteria, like rugdumph´s Sword or the akaviri dai katana, which both have a reach and speed of 1, but are two handed, will be dismissed. They are a special case in which the general rules of the claymore guide apply, just utilizing less reach and more speed.
So, starting off, what Characters can properly utilize this weapon?
The longsword is quite versitile, sacrificing neither reach nor speed while also excelling at neither. They can be used in combination witha a shield, which makes them good for tanks and Allrounders. However,they can also be used without shields, as one would when wanting to have 100% spell effectiveness.
This weapon is ideal for fast-pace combat. Its lack of reach is remedied by the increase in speed. The forward power attack is pretty fast and extends your reach considerably, since you cover quite a bit of groung while performing it.
Because all one handed weapons have the same stealth multiplier, the longsword is the best choice of weapon for the assassin, as they have the highest base damage, but also offer decent DPS once detected.(maces are a bit too slowin my opinion)
Damage-wise, they are fairly alright. However, unless you´re aiming to use umbra or goldbrand, the longsword isn´t the optimal choice for Damage. (On-hit or DPS) otherwise, they work in almost any situation
Lastly, the biggest pro for using this type is the sheer number of powerful artifacts that fall under it. most of the really powerful weapons in the game fall under this cathegory. while the strongest indiviual weapons are a claymore and a warhammer respectively, the longsword has the biggest selection of endgame weapons.
As for the usage in combat, it´s actually fairly simple. In my opinion, the longsword nis the easiest weapon to get used to. The forward power attack is much easier to land than that of a claymore or dagger, due to the higher speed and reach respectively. As with every weapon, the direction of your power attack can be slightly altered after initiating it. However, the longsword barely benefits from this, as the mediocre reach rerely puts you out of your enemies range while having them within yours. the relative speed at which you perform power attachs also means that you´ll rarely ever need to utilize this feature.
The backwards power attack is actually easier to land than the claymore´s if your speed is high. The difference in distance travelled is bigger than the difference in reach. Couple this with toggle walk before initiating the attack and you´ll be able to hit with this attack pretty reliably.
In conclusion, the longsword is easy to learn, still pretty easy to master. I would reccomend this weapon for new to semi experienced players.
ideal for a first playthrough. There is almost always something for you to upgrade into as every material in the base game and all expansions have a representative of the longsword cathegory. (the only exception being gold weapons from shivering isles.)
For long time players, i would recommend something slightly more challenging however, like the claymore or shortsword.
Haven´t seen the first chapter?