Overview
A cutscene showing Caelus and Alloy Mechatron: King Pom-Pom challenging each other.
Alloy Mechatron: King Pom-Pom is the second Boss Enemy encountered in Planarcadia, introduced in Honkai: Star Rail Version 4.1: Unraveled for Daybreak. Lore wise, it is a giant Mechatron resembling Pom-Pom that is being piloted by the Daybreak Squad, almost all of whom have been driven mad after the effects of Happiness Surgery and are powered by a mysterious Supplicant Mask implied to be owned by someone else. As a boss enemy, it appears randomly in end-game content, so it's important to always be aware on how to deal with it. While the fight does go smoother with Elation DMG, there are some other strategies that may prove useful which will be discussed below. Alloy Mechatron: King Pom-Pom will often summon "Alloy Pommies" to join it, although one will always join The Trailblazer's party for some reason.
It is considered as an Imagenae Enemy, and is the boss counterpart of the "Alloy Pommy" enemies as well as the Daybreak Squadron. Technically, it could also be considered an Enemy counterpart of the NPC Pom-Pom and the Enemy SD Civillian Mechatron.
If you enjoyed the guide or found it useful, don't forget to leave a comment and a like! If you have any further questions about the boss or HSR in general, I'll be quick to answer!
UPDATE HISTORY:
2026/04/29: Guide Released.
Data Bank Bio
Alloy Mechatron: King Pom-Pom in the Data Bank.
Alloy Mechatron: King Pom-Pom
"Who can handle the wild, untamed power of the Astral Express!? Pom-Pom, now beyond control, has transformed into the Alloy Mechatron: King Pom-Pom.
King Pom-Pom is a powerful mechatron obsessed with cleanliness and order. By its standards, this place is a mess and needs a thorough! Deep! Clean!"
"Alloy Pommy"
"Mechatrons providing security and cleaning services for Star Rail FEST. They're hardworking, brave, responsible, they take initiative, and... and... and make sure Planarcadia stays spick and span!"
Battle Notes | Venue Protocol Enforcer
The "Alloy Pommy" targeting Alloy Mechatron: King Pom-Pom
During the battle against Alloy Mechatron: King Pom-Pom there is a special action called Venue Protocol Enforcer that appears in the Action Bar. When Venue Protocol Enforcer takes place, two Enemy "Alloy Pommies" will join Alloy Mechatron: King Pom-Pom and one ally "Alloy Pommy" will join the Team. "Alloy Pommy" has a Basic ATK, a Skill and a Talent that can be used during battle:
Housecleaning | "Alloy Pommy" deals 400% Quantum DMG to a single Enemy. Aha will gain 5 Punchline.
Dirt Water Slinging | "Alloy Pommy" will deal 300% Quantum DMG and 1.5% Enemy Max HP True DMG to a single Enemy. This attack consumers 20 Charge Value and will remove one stack of Lasting Antibac from Alloy Mechatron: King Pom-Pom.
Extremeflash Charge | Whenever Aha gains Punchline, "Alloy Pommy" will gain 1 Charge Value. Upon reaching 20 Charge Value, allows the use of Dirt Water Slinging.
Battle Notes | Steam Wash
Alloy Mechatron: King Pom-Pom under the effects of Steam Wash.
Whenever Alloy Mechatron: King Pom-Pom uses High-Temp Sterilization Mode, it will enter Steam Wash. While in Steam Wash, its DMG dealt will increase by 30% and the DMG taken will be reduced by 30% per stack in the first phase and 45% in the second phase. The only way to get rid of Steam Wash is to remove all of the Lasting Antibac stacks on Alloy Mechatron: King Pom-Pom.
To remove Lasting Antibac, you will need to attack Alloy Mechatron: King Pom-Pom using "Alloy Pommy's" Dirt Water Slinging.
Battle Notes | The Path of Elation
Aha's depiction in the Action Menu.
Much like @SparxiConOfficial before it, Alloy Mechatron: King Pom-Pom has various mechanics tailored to Aha and other Elation Characters. As such, it is recommended to at least bring one of the following Characters when fighting it:
- The Trailblazer: Elation (How to obtain: Free)
- Yao Guang (How to obtain: Event Warp)
- Sparxie (How to obtain: Event Warp)
- Silver Wolf Lv.999 (How to obtain: Event Warp)
- Evanescia (How to obtain: Event Warp)
If the player has no Elation Characters, they can still take advantage of Aha Instant through Aha THEMselves attacking the opponents.
The following are all the ways that Elation mechanics are used in the fight:
- Whenever the Team is hit by Alloy Mechatron: King Pom-Pom's Zero-Blind-Spot Cleanse, Aha will gain 3 Punchline.
- Whenever the Team is hit by Alloy Mechatron: King Pom-Pom's Potent Foam Soap, Aha will gain 2 Punchline.
- Whenever the Team is hit by Alloy Mechatron: King Pom-Pom's Saturation Cleaning!, Aha will gain 5 Punchline.
- Whenever the Team defeats an "Alloy Pommy", Aha will gain 5 Punchline.
- Whenever an ally "Alloy Pommy" uses Housecleaning, Aha will gain 5 Punchline.
- Whenever Aha gains 1 Punchline, "Alloy Pommy" will gain 1 Charge Value.
Battle Notes | Team Composition
Once again, while Elation Characters are definitely more suitable for the fight against Alloy Mechatron: King Pom-Pom, they aren't necessary and the fight can be cleared with little difficulty if "Alloy Pommy" is used correctly. Alloy Mechatron: King Pom-Pom shares all of its weaknesses with "Alloy Pommy", meaning that there is no need to focus on one or the other when team building.
For F2P units, there are a few decent options to choose from when dealing with Alloy Mechatron: King Pom-Pom. Yukong, March 7th: The Hunt and The Trailblazer: Harmony can all deal Imaginary DMG to inflict Weakness Break. As such, March 7th: The Hunt is one of the best DPS units to bring to this battle, while I wouldn't recommend The Trailblazer: Harmony over certain other units unless you have Firefly. Asta and The Trailblazer: Preservation can both hit the entire Enemy team with Fire DMG making them both useful for the battle, especially considering the utility both members bring outside of DMG. If you don't have any Elation Characters, this is the best Trailblazer counterpart to bring. Serval and The Trailblazer: Elation can deal Lightning DMG, although I would only use The Trailblazer: Elation if you have another Elation Character or are confident enough in their DMG that their extra Punchline gain is worth more than The Trailblazer: Preservation's shields. As always, Lynx is an excellent healer and March 7th: Preservation can also be used to sustain if you're fine with losing her Imaginary DMG.
Other units that can DMG multiple opponents with elements that cause Weakness Break are also very useful, such as Firefly, Aglaea or Welt. Using Elation Characters that can hit weaknesses such as Sparxie or Silver Wolf Lv.999 are perfect for this battle as they can take advantage of Punchline gain in addition to the AoE attacks they already use. In addition to this, as The Trailblazer: Elation is free, it can help players get used to the increasing amount of Elation-related mechanics that the bosses of Planarcadia use. If the player wants to use more supports and let "Alloy Pommy" be their main source of DMG, Abundance Characters that can hit enemy weaknesses such as Lingsha, Bailu or Luocha may also be helpful.
It should be noted that all enemies in this fight have 20% DMG RES for every Element that they are not weak to. As such, it may be for the best if you avoid bringing DPS units who focus on Physical, Ice, Wind or Quantum DMG unless you have well-built teams that capitalize on this DMG specifically (or you have Silver Wolf, in which case weaknesses are more of a light suggestion than a rule).
The most important rule of team building, however, is to have fun! No point using the OP Mono-Remembrance team if you don't want to! Just use the Characters you like, and you should coast through most of the game's content aside from the very hardest challenges.
Enemy Weaknesses are as follows:
- Alloy Mechatron: King Pom-Pom --- Fire, Lightning, Imaginary
- "Alloy Pommy" --- Fire, Lightning, Imaginary
Examples of F2P-Friendly teams:
- March 7th: The Hunt (DPS), Asta (Sub-DPS / Support), The Trailblazer: Preservation (Sub-DPS / Sustain), Lynx (Sustain).
- March 7th: The Hunt (DPS), Yukong (Support), Asta (Support), The Trailblazer: Preservation (Sustain)
Examples of Stellar Warp teams:
- Welt (DPS), Himeko (DPS), Clara (Sustain), Bailu (Sustain)
- March 7th: The Hunt (DPS), Welt (Sub-DPS), Yukong (Support), Bailu (Sustain)
- Himeko (DPS), Asta (Support/Sub-DPS), The Trailblazer: Preservation (Sustain), Yukong (Support)
Examples of Celestial Invitation teams:
- Literally any of the above, just replace Clara, Yukong or Asta with Silver Wolf. If your team deals more than 2 DMG, she solos.
Examples of Event Warp teams:
- Silver Wolf Lv.999 (DPS), Sparxie (Sub-DPS), Yao Guang (Support), Huohuo (Sustain)
- Firefly (DPS), The Dahlia (Support), Fugue (Support), Lingsha (Sustain)
- Aglaea (DPS), Sunday (Support), Robin (Support), Huohuo (Sustain)
- Silver Wolf Lv.999 (DPS), Sparkle (Support), The Trailbazer: Elation (Support), Huohuo (Sustain)
Moveset | Alloy Mechatron: King Pom-Pom (Phase 1)
Alloy Mechatron: King Pom-Pom's appearance in battle.
Soulmend Shears | Alloy Mechatron: King Pom-Pom deals 300% ATK Quantum DMG to one Character.
Zero-Blind-Spot Cleanse | Alloy Mechatron: King Pom-Pom deals 300% ATK Quantum DMG to all Characters. Aha gains 3 Punchline.
High-Temp Sterlization Mode | Alloy Mechatron: King Pom-Pom will inflict itself with Steam Wash and give itself 2 stacks of Lasting Antibac.
- Steam Wash: Alloy Mechatron: King Pom-Pom deals 30% more DMG. Alloy Mechatron: King Pom-Pom takes 30% less DMG from attacks. Alloy Mechatron: King Pom-Pom will take 10% Max HP DMG when Steam Wash is dispelled. Steam Wash will be dispelled upon the removal of all Lasting Antibac stacks from Alloy Mechatron: King Pom-Pom.
- Lasting Antibac: Alloy Mechatron: King Pom-Pom will take reduced DMG. This effect stacks.
Scrubber's Mutiny | Alloy Mechatron: King Pom-Pom will add Venue Protocol Enforcer to the Action Order.
- Venue Protocol Enforcer: Alloy Mechatron: King Pom-Pom will summon 1 "Alloy Pommy" as an Enemy. 1 "Alloy Pommy" will appear as an ally that can be controlled.
Moveset | Alloy Mechatron: King Pom-Pom (Phase 2)
Alloy Mechatron: King Pom-Pom when affected with Raring to Go.
Soulmend Shears | Alloy Mechatron: King Pom-Pom deals 300% ATK Quantum DMG to one Character.
Zero-Blind-Spot Cleanse | Alloy Mechatron: King Pom-Pom deals 300% ATK Quantum DMG to all Characters. Aha gains 3 Punchline.
High-Temp Sterlization Mode | Alloy Mechatron: King Pom-Pom will inflict itself with Steam Wash and give itself 2 stacks of Lasting Antibac.
- Steam Wash: Alloy Mechatron: King Pom-Pom deals 30% more DMG. Alloy Mechatron: King Pom-Pom takes 30% less DMG from attacks. Alloy Mechatron: King Pom-Pom will take 10% Max HP DMG when Steam Wash is dispelled. Steam Wash will be dispelled upon the removal of all Lasting Antibac stacks from Alloy Mechatron: King Pom-Pom.
- Lasting Antibac: Alloy Mechatron: King Pom-Pom will take reduced DMG. This effect stacks.
Scrubber's Mutiny | Alloy Mechatron: King Pom-Pom will add Venue Protocol Enforcer to the Action Order.
- Venue Protocol Enforcer: Alloy Mechatron: King Pom-Pom will summon 1 "Alloy Pommy" as an Enemy. 1 "Alloy Pommy" will appear as an ally that can be controlled.
Potent Foam Soap | Alloy Mechatron: King Pom-Pom will deal 150% ATK Quantum DMG to all Characters and apply Work is Bliss to itself.
- Work is Bliss: When Alloy Mechatron: King Pom-Pom uses Soulmend Shears, it will trigger Shiny, which deals 2% Max HP True DMG to a Character and gives Aha 5 Punchline. When Alloy Mechatron: King Pom-Pom uses Zero-Blind-Spot-Cleanse it will trigger Pristine, which recovers 1 Skill Point for Alloy Mechatron: King Pom-Pom.
Duty Prep in Progress | Alloy Mechatron: King Pom-Pom will apply Raring to Go to itself and Weakness Protected to itself. Alloy Mechatron: King Pom-Pom will use Saturation Cleaning! next turn.
- Raring to Go: Alloy Mechatron: King Pom-Pom will use Saturation Cleaning! next turn and enter a unique idle animation.
- Weakness Protected: Alloy Mechatron: King Pom-Pom cannot be Weakness Broken.
Saturation Cleaning! | Alloy Mechatron: King Pom-Pom will deal 800% ATK Quantum DMG to all Characters. Aha will gain 5 Punchline.
Moveset | "Alloy Pommy"
An "Alloy Pommy" in battle.
Housecleaning | "Alloy Pommy" will deal 300% ATK Quantum DMG to one Character.
Dirt Water Slinging | "Alloy Pommy" will deal 200% Quantum ATK to one Character and reduce their DEF by 50% for 2 turns.
Circuit Malfunction | When "Alloy Pommy" is defeated by the Team, Aha will gain 5 Punchline.
Extras | Achievements
Two Eager for Battle Achievements can be earned when battling Alloy Mechatron: King Pom-Pom:
- Every Drop Counts | Remove Steam Wash from Alloy Mechatron: King Pom-Pom.
- Bubble Trendsetter | Alloy Mechatron: King Pom-Pom triggers Shiny 3 times in one battle.
Extras | Soundtrack
During the battle against Alloy Mechatron: King Pom-Pom 1 Soundtrack will play:
- Listen! The Engines Roar! | Plays during the battle against Alloy Mechatron: King Pom-Pom. The Phonograph Record is obtained upon completing the Trailblaze Mission Simulacra and Simulation, or Even the Just.
Currency Wars | Unique Differences
When battling Alloy Mechatron: King Pom-Pom in Currency Wars, there are some unique aspects to the fight:
- Steam Wash only boosts Alloy Mechatron: King Pom-Pom's DMG by 20%
- Lasting Antibac only boosts Alloy Mechatron: King Pom-Pom's DEF by 15%/25%.
- Saturation Cleaning! will only grant Aha 4 Punchline.
- A third phase is added in between each phase, with the only difference being that Potent Foam Soap is missing and High-Temp Sterilization Mode isn't immediately used.
Writer's Notes | Question of the Day!
Back again with another Planarcadia guide! Again, I loved Penacony and Amphoreas, and it looks like Planarcadia's gonna be the same way! Honestly, the Happiness Surgery arc was quite exciting and the mix between cool, comedic and creepy when fighting King Pom-Pom was just the cherry on top for such a fun storyline! I didn't get to use any Elation Characters when I first fought this boss (I'm sorry Sparxie, but Evernight needed me!) but the use of the Alloy Pommies to help us fight was still a really fun way to gain Punchlines. The moment I realized Aha helps us fight in this planet I locked in like you wouldn't believe.
Still, I'm super excited for what's to come and have been enjoying the Anniversary greatly! As always, I hope you enjoyed the guide, wish you luck on all your Warps, and encourage you all to make some friends to find some cats!
(btw, my UID is 702511879, if anyone wants some of my cats. If I get Akivimeow, I'll be sure to let you know! As of writing this, I have the Phainon, Sparkle and Yao Guang cakes!)
Hope you enjoyed the guide, Partner!
Writer's Notes | Official Artwork / Renders
Official Artwork of Alloy Mechatron: King Pom-Pom
Official Render of "Alloy Pommy"
