Gear Review
All of the gear sets involved contribute to stacking all potential mitigation/healing buffs while getting a good amount of Ultimate to use for yourself and the group.
Malubeth, the monster set, will not only provide a good amount of healing which scales off of your Max Health but also grants Major Vitality which stacks with the Mystic Guard's Minor Vitality if used. If you find that you don't care for the Healing bonuses, Bloodspawn is an incredibly solid alternative monster set for more Ultimate gain and resistances.
Arkasis is the primary 5x set used as it grants 44 Ultimate to not just yourself but to the 3 other group members in your dungeon party as well. This coupled with the usage of Tripots on top of the 3x Potion Acceleration enchantments on the 3x Infused jewelry pieces is quite powerful when considering the Nightblade passive of Catalyst and the Argonian passive of Resourceful.
Saxhleel's Champion is on one bar, and this is preference as to whether you want more Major Force with an Aggressive Horn or the existence of Major Force with a non-Aggressive Horn ultimate. An alternative set to Saxhleel's that can also be easily one-barred is Akaviri Dragonguard for the Ultimate cost reduction.
Vateshran Sword and Board is on the other bar for the pull in. This will let you avoid using the Fighters Guild skill Silver Leash if Stamina sustain is an issue while also granting Major Maim to anything around you within 8 meters.
Decisive traits on the weapons will help the additional Ultimate generation.
Skills Review
Power Extraction is the Stamina-based counterpart of Sap Essence, the more common Magicka-based morph however we want Power Extraction as it debuffs anything around us with Minor Cowardice, something that helps us mitigate incoming damage for our group.
Pierce Armor is the standard melee taunt that provides both Major and Minor Breach for enemy armor resistances.
Dark Cloak is your primary heal-over-time and burst heal for most situations. You can couple this with Resolving or Echoing Vigor if you want even more healing.
Heroic Slash is another function of gaining Ultimate as it offers the unique modifier of Minor Heroism which stacks with Arkasis and the Nightblade Catalyst passive.
Mystic Guard can be nice to run but there will be times when you need to swap it for Inner Fire, the Undaunted ranged taunt or a different skill should the situation demand it. This will grant you two slots if ever needed.
Refreshing Path is a nice way to keep up a group Heal over Time while procc'ing your Major Resolve which is also proc'ed by your Dark Cloak. It also grants Major Expedition depending.
Mirage is another skill to gain more mitigation particularly against AoE based attacks while also granting additional resistances through Minor Resolve which stacks with the Major Resolve. Reverberating Bash is the skill needed to proc the Vateshran Sword and Board's pull and Major Maim.
Craft
Warfare
Fitness
Champion Points Review
Pretty standard Warfare slottables but we do put in Swift Renewal which affects our Healing over Time skills' values from Refreshing Path and Dark Cloak. As we don't have Defensive Stance or the frost shields from casting Blockade of Frost on a frost staff, we don't need Ward Master. An alternative slottable for Fitness could be Bracing Anchor.
Introduction (Update 32, Deadlands)
This build is NOT recommended to take to Veteran Trials.
Apex is intended to be a fun ultimate-generating tank build on a Nightblade as the spec meshes incredibly well with the Nightblade class toolkit. It's primarily meant for all 4 man content. Post-U32, Nightblade tanking saw slight buffs such as the Dark Cloak heal (which scales off of your Max Health). Unlike the previous Nightblade tank build iterations, this will simply focus on tanking and taking as much damage as possible while consuming as many potions as possible to upkeep Ultimate generation in contrast to dealing damage as a 'sap tank'.
For a beginner's guide to tanking in The Elder Scrolls Online, you can refer to this guide.
Recommended Races for this build are Imperial, Nord and Argonian. For race recommendations you can refer to this video. Note that the Attribute allocation may differ depending on your race. For the purpose of the build showcase, we used Imperial.
Recommended potion for this build is an Essence of Health (tri-stat).
Recommended poisons for this build is Drain Magicka Poison IX.
Recommended food for this build is Bewitched Sugar Skulls.
Recommended Mundus Stone is The Lord.
For gameplay and the video showcasing this build, refer to the video.