Formosus the Undying - Blood, Frost, and Death Boss Guide

Formosus the Undying is a single phase fight with minion mechanics. The fight is largely straightforward but does have several dangerous mechanics that players need to understand in order to defeat this boss.

In this guide, we cover the rewards, boss mechanics, and provide a strategy for defeating this boss.

For more information on the Timeline this boss is found in check out Blood, Frost, and Death Timeline Guide.

Formosus the Undying


All timeline bosses have a pool of exclusive Uniques that can drop. They also provide the player with a Blessing, which is a permanent buff to either power or farming/leveling efficiency. Just like Uniques, each boss has their own exclusive Blessing pool.


Formosus can drop 4 different Uniques and one Set Item:

  • Last Steps of the Living has a 50% chance to drop. It is mutually exclusive to Frozen Eyes of Formosus, meaning you always get one or the other, but not both. It can drop from both normal and empowered versions. The drop rate is not affected by corruption.
  • Frozen Eyes of Formosus has a 50% chance to drop. It is mutually exclusive to Last Steps of the Living, meaning you always get one or the other, but not both. It can drop from both regular and Empowered versions. The drop rate is not affected by corruption.
  • Frostbite Shackles is a rare drop. The drop rate is increased by higher Corruption. It can technically drop off normal Formosus; however the area level must be increased to at least 74 for it to drop. We recommend farming this on Empowered.
  • Eulogy of Blood is a rare drop that can only be found in Empowered. Increases in Corruption improves the drop rate of this item.
  • Lich's Scorn is a relatively common drop. It can drop off any difficulty and any amount of Corruption.

See the Monolith Timeline Guide for more info on Corruption.


The Blessings of this Timeline are focused around increasing drop rates of weapons. Which one you should choose is dependent upon what kind of weapon you want to farm.




  • Ambition of the Empire
  • Chill of Death
  • Cruelty of Formosus
  • Enmity of the Clans
  • Favor of the Wengari
  • Remorse of Heorot
  • Resolve of Frost
  • Savior of the North
  • Scars of Blood
  • Shards of Unity
  • Subtlety of Slaughter
  • Vigilance of the Damned
  • Grand Ambition of the Empire
  • Grand Chill of Death
  • Grand Cruelty of Formosus
  • Grand Enmity of the Clans
  • Grand Favor of the Wengari
  • Grand Remorse of Heorot
  • Grand Resolve of Frost
  • Grand Savior of the North
  • Grand Scars of Blood
  • Grand Shards of Unity
  • Grand Subtlety of Slaughter
  • Grand Vigilance of the Damned

Boss Mechanics


Formosus teleports to a new location. He can teleport to anywhere in the arena which means he often teleports to somewhere off screen. Teleport does no damage.

Ice Patch

Formosus places a large patch of ice on the ground that Slows. It does no damage.

Undead Wengari

Formosus is accompanied by three Undead Wengari Axe Throwers and an Undead Wengari Matriarch. The axe throwers have a projectile that deals low Physical Damage. The Matriarch has a Melee Attack and a Leap Attack that causes an Earthquake with an Aftershock. Both deal Primarily Lightning Damage but the Earthquake is far more deadly.

Resurrect Wengari

Formosus resurrects one Undead Wengari that has been slain in combat.

Spirit Beam

Formosus channels a large beam in front of him for several seconds that deals high Necrotic Damage and gets stronger over time.

Frost Spirit

Formosus fires several projectiles that seek out the player and deal low Cold and Necrotic Damage

Ice Vortex

Formosus places several tornado-like DoTs on the ground that slowly move in random directions and deal Cold Damage that gets stronger over time.


When you go into a timeline boss fight, you carry any modifiers that are active from running echoes. Some of these modifiers can be especially dangerous, while some can actually bring value with little or no downside.

Avoid These Modifiers

  • Critical Strike Avoidance - If you're a Crit based build and have sufficient Crit to be noticeable.
  • Enemies have +X Critical Strike Chance - Avoid these if you don't have capped Critical Strike Avoidance.
  • Enemies have a chance to Dodge - Any builds that rely on Hitting the enemy (including DoT builds that apply Ailments on Hit) should avoid this modifier (except for Rogues with Focus Fire).
  • Enemies heal if they have not been damaged recently - Only take this if you're confident you'll never go 4 or more seconds without damaging the boss.
  • Frenzy and Haste + Berserk - Individually these are manageable (although you may still want to avoid them if you can). Together they can make a boss very difficult to deal with as they significantly speed up the mechanics of the fight. Don't take these unless you're comfortable with the mechanics and confident that the additional speed of the fight won't be a problem.

Take These Modifiers

  • Anything that affects Rare enemies - Bosses are not considered Rare enemies, so those modifiers do not apply to the encounter. However, the rewards do. This is an easy way to boost the value of a fight for any build without increasing difficulty.
  • Enemies have +X Critical Strike Chance when Crit capped - If you're Crit capped, then this modifier provides no extra difficulty.
  • Critical Strike Avoidance on a DoT build - DoTs can't Crit, so this won't matter.
  • Enemies have a X% chance to receive a Glancing Blow when hit on a DoT build - Similar to Crits, Glancing Blows only apply to Hits.
  • Enemies have a chance to Dodge on a build that uses a DoT skill - Ailments generally need to Hit to be applied, so don't take this if you're relying on Hits to stack your DoTs. However, some skills have the DoT tag, meaning they don't Hit. DoTs can't be Dodged, so your damage is unaffected.

Boss Strategy

Formosus is a single phase fight. He has all of his abilities from the start, meaning this fight does not get more challenging over time. Formosus also has four Undead Wengari (three Axe Throwers and one Matriarch) that fight with him and can be resurrected if they fall in battle. Damage is mostly Cold and Necrotic, with the Wengari dealing mostly Lightning Damage, so cap all three of these Resistances. The fight itself is straightforward and not particularly challenging but there are mechanics that can kill unsuspecting players. Here are some general strategies:

  • The Axe Throwers aren't dangerous, but the Matriarch is. She can also be difficult to track while paying attention to Formosus and her Leap Slam is fast so there isn't much time to react. Killing the Axe Throwers and the Matriarch forces Formosus to choose only one to Resurrect, giving you a much better chance of not having to deal with the Matriarch for long stretches of the fight.
  • When Formosus Teleports he often moves off screen. Be prepared to search for him.
  • Spirit Beam deals a lot of damage but is easy to avoid. If there is an Ice Patch on the ground it becomes significantly harder. Having a movement ability makes it much easier to deal with these overlapping mechanics.
  • Frost Spirit does low damage and can be tanked. The homing aspect of the skill makes it difficult to dodge so focus on other mechanics and use a potion if you need to.
  • The damage from Ice Vortex ramps up over time and becomes deadly. Make sure to account for where these are at all times and stay out of them. They start off with low damage so if Formosus places one on top of you there's enough time to move out before it starts to hurt.

Overall, there's a lot of moving parts to this fight but most of them don't matter. What does matter is Spirit Beam, Ice Vortex and Leap Slam. If you can avoid those three attacks you will kill Formosus.


  • The Blessings for this timeline are all focused around increasing drop rates of weapons.
  • Formosus is a relatively easy single phase fight with straightforward mechanics.
  • Formosus has Undead Wengari with him that he can Resurrect. The Matriarch is the most challenging but you should kill all of them to make Formosus choose which one he Resurrects.
  • Damage is mostly Cold and Necrotic, with the Wengari dealing mostly Lightning Damage, so cap all three of these Resistances.
  • Having a movement ability in case you get stuck in Spirit Decay with an Ice Patch is a good idea.
  • Avoiding Spirit Beam, Ice Vortex, and the Matriarch's Leap Slam is the key to victory.



Written by McFluffin.
Reviewed by Facefoot, Lizard_IRL, Raxxanterax.


Feb 5th 2023
Article created