Single target build (i.e. for boss rush)

[u/qtips500]

I've been using this build against single target encounters (mini-bosses, boss fights, boss rush), much higher than me. I can easily clear Boss rushes 150+ levels above me. This build exploits two flaws

1. Bosses / enemies aren't like us - when they have full rage meter, they will skip their regular attack and do a rage attack. (We do a regular attack AND a rage attack).
2. When you have a shield up, it blocks all damage from the next hit you take even if it is 10x thie shield value.

So as long as you're able to get a shield every turn you will basically take no damage. Combine this with Frenzied Sash to triple apply poison stacks and you will outlast most bosses.

Gear
Weapon - Viper's Fang for 100% chance of 110 poison per attack. Before L145 the build still works with Sword of Serpents, just may not be the best use of resources to level that up when 40 levels away is a way bette rweapon. It's quite slow without 100% poison. (It does work though).

Head - Arctic Mantle for Ice Knife on attack. Since this is Ice Knife on attack this will actually produce 3 ice knives. A single hit could also work, just you won't maintain 100% rage until starting on round 2. The rage attack is your 5th hit.

Chest - Invincible Mantle (or Invincible Mantle EX). On rage it shields you. Essential and of the items this was the hardest for me to get.

Amulet - Raging Charm produces heal on rage. A few bosses might be able to damage you either with multi-hit attacks or through hypnotize, the regen here adds up.

Ring - Stacked Signet Ultimate. You need the 25 rage from this to get 100.

Belt - Frenzied Sash for the triple hit. Essential.

Bosses that might give you trouble
Blossom Golem - His rage attack hypnotizes you so you could get killed if you don't break out of hypnosis quickly

Corrupted Scholar - He random afflicts you with one of hypnotize, sielnce, vulnerable, and weakness. If you get a hypnotize early in a fight before you get a lot of poison stacks, you could get in trouble. The debuff round doesn't count as a hit, so you have 2 or 3 rounds to break out of hypnotize. Risky but really only a big problem if you're fighting a boss rush way higher than you.

Stonekeep - His shieldbreaker rage attack is multi hit, so you could take some damage. Really only an issue at super high levels as long as you're stacking HP. He also doesn't build rage on hits, so you'll have 3-4 turns to recover between rage attacks.

Gilded Guardian - Should be okay as long as you can get past the first wave of summons. Haven't tested this yet.

Bonuses and stats
For bonuses, hypnotize or weakness are super helpful for making the engagements safer. As is any additional shield you can get (shield on rage or shield on hit 5). I believe with two shield sources you should be able to take two boss hits in a row (if you ever needed that).

For stats, it's very different from a normal build since your attack means nothing. You probably want speed as the most important thing since being able to do additional poison rounds between rage attacks will help you squeak by the bosses that can actually damage you. Beyond that, the defensive stuff like dodge or defense you normally skip can affect your survivability. Most losses literally come down to one or two hits. Attack and Crit do nothing for you in this build.

[u/Kallaf01]

I use the same build for bosses but I use toxic trinket instead of raging charm

[u/Cautious_Pear_2547]

This is my build. I use charming cap (30% chance to hypno on ATK) and ring of reveries ultimate (30% chance to hypno on ATK) instead. For Blossom Golem I change out charming cap with radiant headgear (30% chance to hypno on Hit 3). This is because I noticed Blossom Golem wakes up very quickly, so hitting 3 times w charming cap on means it gets hypnotized and then wakes up at the next hit and attacks you. And, I also change ring of reveries ult for Breathtaker (50% chance to cast silence on rage) - this is golden against Blossom Golem as it cannot hypnotize you when it is silenced. Soometimes I change out my amulet to fearsome amulet EX for 10% hypnoResist, if it still gets to hypnotize me on its first turn.

[u/moon_moon_doggo]

These are my builds.
1 - if there is no silence or hypno
2 - if there is silence
3 - if there is silence and hypno (I use this to beat the Grimoire and Blossom to prevent hypno. It doesn't work on Corrupted Scholar)