Harmonious Choir (Sunday) Boss Guide and How to Beat

Check out this guide to learn how to beat the Sunday Boss fight, also known as Harmonious Choir - The Great Septimus in Honkai: Star Rail. We also have a full details on the Sunday boss fight's best teams, weakness , drops, and abilities.

Harmonious Choir (Sunday) Boss Fight Overview

Harmonious Choir - The Great Septimus Basic Info

Harmonious Choir - The Great Septimus Information
Harmonious Choir - The Great Septimus
Trailblaze Power	x30
Reset Time	Every Monday at Server Reset
World	Penacony
Phases	3 Phases
Weaknesses
Resistances	Control Effects RES

Harmonious Choir - The Great Septimus Summon Info

Echo of Faded Dreams (Phase 1 and 2)	Weaknesses
	Resistances	None

Harmonious Choir (Sunday) Boss Fight Location

Trailblaze Mission Boss

Harmonious Choir - The Great Septimus is a boss that you will first encounter during the Trailblaze Mission, Everything that Rises Must Converge.

Found in Penacony - Penacony Grand Theater

Location	Penacony Grand Theater, Penacony

Harmonious Choir - The Great Septimus is a weekly Echoes of War Boss that can be unlocked after completing the mission, Everything that Rises Must Converge!

Echoes of War Weekly Bosses and Drops

Harmonious Choir (Sunday) Boss Fight Best Teams

Free to Play Team

F2P Team
Serval	Asta	Trailblazer (Imaginary)	Lynx

Trailblazer (Imaginary) excels for this Echo of War fight since they provide Break Effect for the team and allow your party to deal Super Break DMG which is great for reducing the Toughness of the Great Septimus.

Serval will be your main DPS since she can hit multiple enemies with her Skill and Ultimate while Asta provides ATK and SPD buffs for your entire party. Lynx will be the healer and can also cleanse debuffs using her Ultimate.

List of All Free Characters

Fire DPS Team

Fire DPS
Himeko	Topaz	Ruan Mei	Aventurine

Himeko does very well in this fight since she can hit multiple enemies with her abilities and do Follow-Up attacks after enemies get Weakness Broken. Topaz increases the FuA DMG enemies take while also doing attacks of her own.

Ruan Mei is amazing here since she can increase Break Efficiency for the whole party, along with the other offensive buffs she brings. Aventurine can increase the CRIT DMG taken by enemies and provide team-wide shields.

The Effect RES provided by Aventurine's shields can also help resist the Alien Dream that the Great Septimus can inflict with one of its abilities.

List of All Fire Characters

Lightning DPS Team

Lightning DPS
Acheron	Welt	Pela	Aventurine

Acheron works well here since her Skill and Ultimate can hit multiple targets and reduce their Toughness simultaneously. Welt can apply debuffs such as Slow and Imprisonment while also hitting multiple targets with his abilities.

Pela provides DEF reduction to multiple enemies using her Ultimate. Aventurine provides team-wide shields and increases the CRIT DMG enemies take. His shields also increase Effect RES for the party.

If you have Inherently Unjust Destiny on Aventurine, it can provide an additional debuff to enemies that helps Acheron build up her stacks.

List of All Lightning Characters

Imaginary DPS Team

Imaginary DPS
Imbibitor Lunae	Sparkle	Trailblazer (Imaginary)	Luocha

Imbibitor Lunae excels in this fight since his enhanced Basic ATK and Ultimate can hit multiple enemies and reduce their Toughness simultaneously. Sparkle provides offensive buffs and SP for Imbibitor Lunae.

Trailblazer (Imaginary) increases Break Effect and allows the party to deal Super Break DMG which is effective against the Great Septimus. Luocha can cleanse debuffs while also hitting multiple enemies with his Ultimate.

List of All Imaginary Characters

How to Beat Harmonious Choir (Sunday) Boss Fight

Inflict Weakness Break on Echo of Faded Dreams

Inflicting Weakness Break on Echo of Faded Dreams delays their action as well as the Great Septimus' action, so make sure to inflict Weakness Break on them first. The damage Echo of Faded Dreams takes is also inflicted on it.

AoE Attacks excel in this regard since hitting multiple targets means you will be able to break enemy Weaknesses simultaneously. Your party also gets Walk in the Light which is a shield shared by all party members.

Furthermore, if all of the Echo of Faded Dreams are Weakness Broken when the Great Septimus takes its turn, it won't be able to use Volteggiando or Tempestoso which are heavy-hitting attacks.

Cleanse Alien Dream

The Great Septimus' Vaneggiando ability can inflict Alien Dream on one of your characters. Alien Dream puts a character to sleep which means they cannot take action. The character wakes up after several turns or when attacked.

Make sure to cleanse this debuff using characters with abilities that can remove debuffs such as Luocha or Huohuo. Aventurine's shields that provide Effect RES can also help resist this debuff.

Reduce Toughness in Third Phase

In the third phase, The Great Septimus transforms into Embryo of Philosophy - Sunday. This form has all Type Weaknesses and takes a turn after every action your characters take, but would not attack your party.

After seven turns, it will use an attack that deals massive damage to all targets and ignores DEF. This attack can be fatal, so reduce its Toughness as much as you can before the eighth turn or try to inflict Weakness Break on it.

For each Toughness bar broken, the party gains Walk in the Light which is a shared shield that can help mitigate the damage from its attack. Characters that emphasize on Break Effect like Trailblazer (Imaginary) and Ruan Mei help in this phase a lot.

Harmonious Choir (Sunday) Boss Fight Talents and Abilities

All Boss Fight Phases
Phase 1	Phase 2	Phase 3

Phase 1 - Harmonious Choir - The Great Septimus Skills

All Talents and Abilities
◆	Grazioso (Ability) Deals minor Imaginary DMG to a single target.
◆	Maestoso (Ability) Deals Imaginary DMG to all targets.
◆	Vaneggiando (Ability) Makes a single target have a high chance of entering Alien Dream.
◆	Accelerando (Ability) Enters the Charge state. Uses "Volteggiando" in the next turn.
◆	Volteggiando (Ability) Makes all Echoes of Faded Dreams that can take action deal Imaginary DMG to a single target. If there are no Echoes of Faded Dreams that can take action, then this ability will fail to launch. After using this ability, restore Toughness for Echoes of Faded Dreams.
◆	Come Un Sogno (Ability) "Harmonious Choir" The Great Septimus summons 4 "Echoes of Faded Dreams." The DMG dealt to the Echoes of Faded Dreams is completely redistributed to "Harmonious Choir" The Great Septimus instead. When this unit and Echoes of Faded Dreams become Weakness Broken, additionally delays action. For every stack of this unit's Toughness that is broken, apply the Walk in the Light state to targets.

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Phase 2 - Harmonious Choir - The Great Septimus Skills

All Talents and Abilities
◆	Grazioso (Ability) Deals minor Imaginary DMG to a single target.
◆	Maestoso (Ability) Deals Imaginary DMG to all targets.
◆	Vaneggiando (Ability) Makes a single target have a high chance of entering Alien Dream.
◆	Accrescendo (Ability) Enters the Charge state. Uses "Tempestoso" in the next turn.
◆	Tempestoso (Ability) Deals Imaginary DMG to all targets, and makes all Echoes of Faded Dreams that can take action deal Imaginary DMG to all targets. After using this ability, restores Toughness for Echoes of Faded Dreams.
◆	Allargando (Ability) Enters the "If We Live In the Light" state, gains a Shield, increases the DMG dealt, decreases the DMG taken, and makes Toughness immune to reduction.
◆	Come Un Sogno (Ability) "Harmonious Choir" The Great Septimus summons 4 "Echoes of Faded Dreams." The DMG dealt to the Echoes of Faded Dreams is completely redistributed to "Harmonious Choir" The Great Septimus instead. When this unit and Echoes of Faded Dreams become Weakness Broken, additionally delays action. For every stack of this unit's Toughness that is broken, apply the Walk in the Light state to targets.

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Phase 3 - Harmonious Choir - The Great Septimus Skills

All Talents and Abilities
◆	Im Anfang war das Wort (Ability) Enters the Charge state. After 7 turns, uses "Im Anfang war die Tat."
◆	Im Anfang war die Tat (Ability) Deals massive Imaginary DMG to all targets. This DMG application ignores the targets' DEF.
◆	Work of Creation (Ability) "Embryo of Philosophy" Sunday has weaknesses of all Types. While "Embryo of Philosophy" Sunday is in the "Im Anfang war die Kraft" state, it will immediately take action after every action taken by targets and becomes immune to action delay effects caused by targets. When it becomes Weakness Broken, its action is additionally delayed. Moreover, after one stack of its Toughness is Broken, it applies Walk in the Light to targets.

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Summoned Enemies Talents and Abilities

Echo of Faded Dreams Skills

All Talents and Abilities
◆	Afflitto (Ability) Deals minor Imaginary DMG to a single target and delays their action slightly.
◆	Come In Incubo (Ability) All DMG dealt to this unit is taken by the Harmonious Choir instead.

Harmonious Choir (Sunday) Boss Weaknesses and Resistances

Weaknesses

Harmonious Choir - The Great Septimus Weaknesses
Imaginary	Lightning	Fire

Use the characters with the same elements above to easily defeat Harmonious Choir - The Great Septimus!

Resistances

All Resistances
Resistances	Control Effects RES

Avoid using characters with the elements or skills the same as the above. It will lessen the damage against Harmonious Choir - The Great Septimus!

Harmonious Choir (Sunday) Boss Fight Drops and Rewards

Harmonious Choir - The Great Septimus Drops

Ascension Mats and Relics
Lost Echo of the Shared Wish	Lucent Afterglow	The Ashblazing Grand Duke	Watchmaker, Master of Dream Machinations
Possible Light Cone Drops
What Is Real	Dreamville Adventure	Final Victor	Flames Afar
Destiny’s Threads Forewoven	The Day The Cosmos Fell	It’s Showtime

All Items List

Other Item Drops

Items Dropped
Credit	Trailblaze EXP

Characters that Use The Great Septimus Materials

Boothill	Firefly	Jade

All Character Ascension & Trace Materials

Honkai: Star Rail Related Guides

List of All Bosses

Echoes of War Weekly Bosses

Doomsday Beast	Cocolia, Mother of Deception	Phantylia the Undying
Starcrusher Swarm King - Skaracabaz (Synthetic)	Harmonious Choir - The Great Septimus	Shadow of Feixiao and Ecliptic Inner Beast

Echoes of War Weekly Bosses and Drops

Stagnant Shadows Field Bosses

Disciples of Sanctus Medicus - Shape Shifter	Ice Out of Space	Decaying Shadow
Frigid Prowler	Automaton Direwolf	Blaze Out of Space
Guardian Shadow	Stormbringer	Voidranger - Trampler
The Ascended	Aurumaton Gatekeeper	Abundance Sprite - Malefic Ape
Searing Prowler	Aurumaton Spectral Envoy	Dreamjolt Troupe's Sweet Gorilla
Dreamjolt Troupe's Beyond Overcooked	Memory Zone Meme - Shell of Faded Rage	Senior Staff - Team Leader
Present Inebriated in Revelry	Howling Casket

Stagnant Shadow Field Bosses and Drops