Mithrix

 is the final boss of Risk of Rain 2. He is encountered at the apex of Commencement, the moon of Petrichor V and final stage of the game.

Description
Mithrix is an ancient, cyclopian humanoid with godlike powers, much of which he shared with his brother Providence. The growing philosophical opposition between the two siblings worsened to the point that Mithrix was banished to the shattered pieces of Commencement, while Providence took to carrying out his own vision on the world below.

By the time of the events of Risk of Rain 2, Providence had been slain, yet Mithrix's confinement upon Commencement as the King of Nothing continued. It would be the Survivors of the UES Safe Travels who reached the moon via the Celestial Teleporter to put an apparent end to him.

The deeper details and circumstances of Mithrix and Providence's relationship are detailed throughout many of the game's logs, most of which are taken from Mithrix's perspective, including those for, A Moment, Fractured, Bulwark's Ambry and more.

Adaptive Armor
During phases 1 and 3 of the fight, Mithrix has the Adaptive Armor passive which protects him against bursts of damage. Every time Mithrix takes damage, he gains temporary armor equal to $$3000 \bullet (damage / maxHP)$$, or 30 armor per 1% of his max HP dealt. This armor caps at 400 and decays at a rate of 40 per second.

Phase 1
Mithrix starts the battle with basic attacks, which consist of running around, dashing while swiping with his hammer for 200% damage, smashing the ground with his hammer causing an explosion for 1200% damage (with damage falloff) and an additional 1200% damage on a direct hit (although the hitbox is fairly small), and running at the player while firing up to 12 needles for 60% damage each. He can also jump into the air of the center of the stage and slam down, causing a ring-shaped shock wave around the stage which deals 400% damage and the player. The shock wave ends when it reaches the thin line of rocks between the platform where he is first seen.

Phase 2
Mithrix leaves the arena, and several stone pillars rise up around the arena. In place of Mithrix himself, several, , and are summoned and must be defeated. New chimeras are occasionally summoned as the player destroys the initial ones.

Phase 3
Mithrix returns with more powerful and different attacks, occasionally summoning Lunar Chimera Golems and, more rarely, Lunar Chimera Wisps. His moveset is similar to the first phase, but the attacks have additional effects to them. He also becomes more aggressive and attacks more often. His slam leaves a lingering pillar of flames that deals 150% damage per tick and sends 3 small, directional shockwaves similar to the shockwaves from his jump slam attack, dealing 200% damage and applying Cripple. Mithrix also gains an additional attack in which he summons moving lines of flame that spin around him and explode after short delay, dealing 900% damage and applying Cripple. This attack is repeated 4 times.

Phase 4
Mithrix steals all players' items and gains their buffs, except for equipment,, , or. Damaging him will release the items, one by one in the order they were obtained. In multiplayer, the items will be returned to players in round robin order, by player slot. He will fire a burst of projectiles and slowly stomp around the battlefield. At low enough health, he will begin to occasionally kneel and fire fast-moving orbs for 400% damage in eight directions, simultaneously dealing 8% of his current health in damage to himself. If the player has any Halcyon Seeds, will spawn and help the player during this phase. Hitting Mithrix with high damage in this phase will stagger him.

Sometimes Mithrix doesn't take any items and simply skips this phase (this seemingly happens from sources of continuous damage such as ).

Aftermath
Once Mithrix is defeated, all stolen items are returned and the moon begins a detonation sequence with an on-screen countdown. In order to exit Mithrix's arena, the surviving players must jump into one of the floating portals in order to teleport out. The players have 3 minutes to get to the Rescue Ship and complete its holdout event in order to escape, which requires the players to protect the ship by staying near it for 1 minute. Lines of flames will appear all across the map, similar to the columns used by some of Mithrix's attacks. and will spawn and attack the player, but they generally won't enter the protection zone of the Rescue Ship.

Successfully making it to the shuttle will complete the Washed Away challenge and unlock the as a playable Survivor. Additionally, on difficulty, it will complete the The Calm challenge and unlock, and unlocks the mastery skin for each player's current Survivor.

Tips

 * Mithrix cannot climb the pillars that appear on Phase 2, so if the player gets on top of them and uses ranged attacks, Phase 3 and 4 will be very easy. The ranged attack on Phases 3 and 4 can be easily dodged from higher ground as well. HOWEVER, the lines of flame in Phase 3 can still hit the player.


 * and skills are capable of freezing and executing Mithrix, unlike other bosses.
 * The player can use to avoid the entirety of Mithrix's first phase.


 * On-kill items, such as and, are almost useless for Mithrix, as they will not activate unless he kills a player or ally.


 * Mithrix will take but cannot use, , and during Phase 4.


 * If Mithrix takes a in Phase 4, he will begin to almost constantly fire projectiles.


 * Mithrix will take and use the Captain's as well as any  during Phase 4, making the fight significantly harder until they are recovered.


 * Mithrix will take during Phase 4, and he will use it if given the chance. However, players will regain an unspent Dio's Best Friend along with all other stolen items upon Mithrix's first death. If Dio's Best Friend is recovered before Mithrix dies, he won't gain a second life.


 * When the is enabled, two Mithrix will spawn. Players must kill both bosses before they will advance from one phase to the next. However, when one's health is emptied, it will be incapacitated until the next phase.
 * This is especially dangerous if both Mithrix use their fire wheel attack at once, making it exceedingly difficult to dodge.


 * Mithrix steals items from minions, like turrets, but does not use them.


 * During Phase 4, Mithrix will not use his orb attack while his health is above a certain threshold.


 * If the player has any before Phase 4, additional equipment charges remain even after Mithrix takes all the player's items. This can be used to easily finish him off with the, , , etc.


 * During Phase 4, the spawned from  remain with the player and deal significant damage to Mithrix, making the phase noticably easier.
 * Be wary that when Mithrix steals the Empathy Cores, he gains his own Probes which are allied with him that will attack the player.
 * The same thing happens when Mithrix steals the, which is especially dangerous since the ally he will gain is much stronger than a normal Beetle Guard.


 * can be used to effectively and reliably one-shot, or at the very least, severely damage Mithrix. However, this requires exact timing, and the player should ideally have high stacks of, , and/or . When first entering the arena, place the DIABLO Strike in the center of the arena. When the cooldown timer reaches 29 seconds, run to the center of the arena and initiate the fight. During Phase 2, leave 1 enemy alive (avoid any offensive drones or minion items for this to work), then place a DIABLO Strike in the center of the arena. Wait until the cooldown timer reaches 28 seconds and kill the last enemy. If the player has , it will also instantly kill Mithrix when he begins Phase 4.

Version History

 * PC Patch v1.1.1.2
 * Bug Fixes
 * Fixed a crash during the last boss fight


 * Anniversary Update
 * Gameplay Changes
 * Base Health: 1000 (+300 per level) ⇒ 1400 (+420 per level)
 * Added stagger state triggered by taking high damage
 * Item Steal
 * Now consistently returns items as you deal damage, rather than randomly, i.e if you have him at 50% health, you will have 50% of your items back
 * Now consistently returns items to players in multiplayer in order (1, 2, 3, 4, 1, 2, 3, 4) rather than per-player damage
 * Now returns items in the order that you found them, rather than in reverse order
 * Now utilizes
 * Bug Fixes
 * Fixed the final boss’s crystals not being correctly colored


 * PC Patch v1.0.2.0
 * Bug Fixes
 * Fixed the final boss’ shockwaves being fired an extra time for each remote client in the game


 * PC Patch v1.0.1.1 (Build ID No.5440050)
 * Gameplay Changes
 * Developer Notes: The goal with these changes is to make the final phase of the fight more consistent, fix a few softlock scenarios, and to remove a few cheeses. The expectation is that with these changes, the final phase (and only the final phase) will be much easier. We want this to be a fun phase, not a frustrating conclusion
 * Remove “unique” scaling on health and damage. This has a significant reduction on the way his health and damage scales over time, especially later into the run. Expect him to have less than half of the current live build, depending on time.
 * Lunar Shard Attack
 * Projectile Cone: 20° ⇒ 0.5°
 * Developer Notes: The intent for this change is to reduce the cone that the attacks come out of, reducing the chance you randomly get hit by a stray shot.
 * Energy Ball Attack
 * Damage Coefficient: 1000% ⇒ 700%
 * Knockback Force: 400 ⇒ 4000%
 * Projectile Radius: 3m ⇒ 2m
 * Now glows with a stronger effect to make it more visually noticeable, especially when swinging around corners
 * Item Steal
 * Add immunity while channeling.
 * Can no longer use and . He will take them, but will be unable to use them. This is a mechanic we already have in place for a few key items  that can cause softlocks or impossible scenarios.
 * Now steals items from minions, like . He won’t use the items he takes from minions.
 * Minions can now retrieve items for their owner.
 * Add visual effect to being active
 * Bug Fixes
 * Fix Final Boss health bar not showing for clients (including phase 2)
 * Fix final boss fight sometimes not triggering


 * Early Access Content Update 5
 * Major Content
 * Added New Final Boss: ???
 * Added New Monster Lore Entry: ???

Dialogue
Mithrix is unique in that he speaks throughout his fight, with his quotes appearing in the chat box. His dialogue may change depending on what items the player holds or which character they are playing as.

Toggle Dialogue Spawning


 * Pray.
 * Beg.
 * Die.
 * Be slaughtered.

Spawning (when the Player is the Heretic)


 * Regret this journey, Heretic.
 * Die again, Heretic.

Dealing damage (early phases)


 * Bleed.
 * Now is the time for fear.
 * Weak.
 * Frail - and soft.
 * You are nothing.
 * Mistake.
 * Scream, vermin.
 * Break beneath me.
 * Slow.
 * Your body will shatter.

Dealing damage (late phases)


 * BLEED.
 * SCREAM.
 * WHERE'S YOUR INFLUENCE?
 * FLEETING STRENGTH.
 * FRAIL.
 * BREAK.
 * FALSE STRENGTH.
 * DRAIN.
 * DIE, VERMIN.
 * WEAK, WITHOUT YOUR BAUBLES AND TRINKETS.

Player is killed (early phases)


 * Return to dirt.
 * Submit, vermin.
 * Die, vermin.
 * Die, weakling.
 * Become memories.

Player is killed (late phases)


 * DIE.
 * WEAK.
 * USELESS.
 * AS I THOUGHT...
 * VERMIN.

Player is killed as Heretic (early phases)


 * Return to pieces, Heretic.
 * Die again, Heretic.

Player is killed as Heretic (late phases)


 * RETURN TO PIECES, HERETIC.
 * DIE AGAIN, HERETIC.

The Player has Halcyon Seed (final phase)


 * THE GUARDIAN...? IMPOSSIBLE...!
 * THE WRETCHED GUARDIAN!

The Player has Halcyon Seed and Aurelionite is killed


 * YOU CANNOT DEFY ME, GUARDIAN
 * RETURN TO DIRT, GUARDIAN.

The Player has Halcyon Seed and is also the Heretic (final phase)


 * THE HERETIC? THE GUARDIAN? HOW? WHO PULLS YOUR STRINGS, VERMIN?

Mithrix kills a drone


 * Inferior construct. Broken.
 * Primitive scrap.
 * Disassembled.

Mithrix is killed


 * NO... NOT NOW...
 * WHY... WHY NOW...?
 * NO... NO...!
 * BROTHER... HELP ME...!
 * THIS PLANE GROWS DARK... BROTHER... I CANNOT SEE YOU... WHERE ARE YOU...?
 * BROTHER... PERHAPS... WE WILL GET IT RIGHT... NEXT TIME...