Skyrim SE: Alternus - The Black Knight (My Personal Build)

This is the build that I used in my first structured play-through of the game and first build I created. It is what I use every time I start a game on a new version. It is incredibly powerful; powerful enough to use on Legendary difficulty without much trouble.

Race: Go for Breton. Their racial abilities become useless in the late game for this build, but it is invaluable in the early game for Legendary difficulty. They have a 25% resistance to magic and can use their racial ability to gain 50% magicka absorption for 1 minute. We will be achieving 100% magicka absorption later on, so this will be useless.

Standing Stone: I took the Lord Stone straight out of the gate for the extra magicka resistance and armor. I skipped the warrior stone because you level combat abilities really quickly on Legendary due to how many times you have to hit the enemy, and leveling too quickly is kind of a detriment on legendary since enemies scale to your level. The longer you can avoid going up against Draugr Death Lords the better. Later, you should grab the Atronach Stone. If you combine that with the Atronach perk in the Alteration tree and then add Vampire/Necromage combo to it, you will have 100% magicka absorption and spells will no longer affect you.

Stat Distribution: Ignore Magicka, it's useless here. Instead put all of your points into Health and Stamina at a 4:1 ratio, respectively. At lvl 50 you should have 200 Stamina and 490 health.

Skills:

Weapon: As soon as you hit lvl 20, do the Daedric quest to get the Ebony Blade. This weapon may not be the best when it comes to physical damage, but it hits very fast and absorbs 30 health for every hit. As long as you are hitting the enemy, you can't die.

Armor: In the early game, I rad to Solitude and got the Imperial Champion armor from the Creation Club. It is very good armor, but it has it's own enchantments on it already. Once you can get some Daedric armor and have high enchanting, enchant your own gear and ditch the Imperial Champion Armor.

Enchantments: Enchant any piece of armor you can with Fortify Two-Handed. This will make the Ebony Blade's Physical damage more usable. Also get Stamina Regeneration on your armor to mitigate the negative effects of being a vampire in the day time. The health regen problem will be taken care of by the sword and the magicka regen problem won't matter.