Warrior
Titan0.5 Nightfall Titan Build: Slams, Aftershocks, and Freezes!
Welcome to my 
Nightfall 
Titan build everyone! This build is centered around scaling up the slam skill granted by Nightfall, which is called Embrace the Fall, which has a huge base AoE, high base critical hit chance at 15%, and deals a ton of Cold damage.
We're basically using that skill to clear in Weapon Set 1, which is focused on cranking up our AoE on the Passive Skill Tree, and when it comes to bossing we simply swap to Weapon Set 2 to trade off some of that AoE for more damage; you don't need to set any skills to specific weapon sets, you literally just make sure you are in Weapon Set 1 while clearing, and Weapon Set 2 for boss fights.
However, Nightfall's skill has an innate cooldown of 4 seconds; we need to work around this by either stacking cooldown reduction, or destroying Ice Crystals with the Slam portion of the attack. I think both methods are legitimate to pursue, but I ended up socketing 
Grim Pillars and just, manually casting this wherever I want to throw my shield via 
Soaring Midnight.
How Clearing Works
Essentially, we just cast Grim Pillars where we want to throw Nightfall, then slam down on a mob of enemies while destroying Ice Crystals so that we can reset the cooldown and throw it again. As a baseline, this is a two-button clearing build; and honestly, you could get by with just that. I would recommend just making sure you aren't throwing Nightfall into a terribly crowded situation and that you are side-strafing as you are waiting for it to get into position for your slam.
For bonus points, you can also mark targets with 
Freezing Mark for an easy Cold Damage buff while clearing. I know I know, now it's a 3 button build, but this makes a noticeable difference and is very helpful for 200% Delirious maps.
Speaking of which, this build is fully-capable of clearing those on such a small budget; only ~30 divs! However, just be very cautious as to where you are actually slamming down while clearing; the AoE is so big with this build that you can honestly just Grim Pillars and chuck Nightfall towards the very edge of groups, and end up wiping pretty much everything on the screen anyway.
How Bossing Works
For bossing, we swap to Weapon Set 2 (don't forget this!), and we basically want to hit the boss with Empowered versions of our Nightfall slams, via 
Infernal Cry. However, Infernal Cry is getting a lot more Empowered Attacks due to Vruun's Aftermath, so we want to slap down some Grim Pillars, cast an Infernal Cry, and then we are ready to Freezing Mark and Slam away. For bonus points, we also run 
Refutation, and you can pop this AFTER you cast Grim Pillars so that we can reset the cooldown of your slam after consuming all of your Runic Ward; make sure you get a couple of sockets dedicated to boosting Runic Ward generation. You may also spend time at the beginning of the fight using 
Resonating Shield to build up some Rage and break the bosses armour.
We're basically fishing for big crits while doing this, which you should see while hitting the target with slam after slam, but sometimes you'll get unlucky and not see some crits. Shouldn't be too often since we are hitting ~52% crit chance with this setup. Garukhan's Resolve is an expensive but VERY USEFUL item for this build in that regard, also for clearing too tbh.
More details below on gearing, skill gems, etc. Read on!
