SMT IV: Apocalypse - Trumpeter (Apocalypse Difficulty, No Skill Inheritance)

Rules:
1. All battles are fought on Apocalypse difficulty.
2. Experience gain is minimized by only fighting fiends, beginning at level 76.
3. Demons may only be fused or recruited with their default skillsets, and skill changes are not allowed.
4. No stat boosting items or apps, including Armor Boost Kits.
5. Consumable use is unlimited since Chakra Pots, Bead Chains, and Great Chakras are all farmable in the Black Card shop or with the Trade app.
6. There are no limitations for whispering skills to Nanashi, so long as the demons with those skills are available. Demons may be leveled up with experience items to learn their full skillsets.

Although Trumpeter is one of the only memorable horde boss fights in either SMT IV and Apocalypse, there's not much else in this battle that makes it interesting. His skillset is pretty limited; early in the battle, his only attacks are all four Ma-dynes and Riot Gun. As the battle goes on, he gains access to "Will of ____" piercing skills and Smile Charge, but neither of those add much to the battle. As long as Nanashi's team doesn't have many weaknesses, the piercing elementals aren't very notable, and Magaon takes care of Smile Charge. Evil Melody, Trumpeter's unique skill, is only used when he has a smirk, so it doesn't really see any use when Nanashi's team doesn't have elemental weaknesses and Magaon is used. The most annoying skill Trumpeter has is Silent Prayer, which he uses periodically to wipe out buffs and debuffs and really draw out the battle.

Defensively, Trumpeter is by far the most annoying of the fiends. He only has a weakness to gun and has a massive HP supply of about 120,000, which is meant to account for taking more damage from AOE attacks. Unfortunately, AOE attacks are much less useful on Apocalypse difficulty due to decreased accuracy, so relying on attacks like Heaven's Bow to deal damage doesn't work as well as on lower difficulties, but there aren't any better options. I gave Nanashi Judgement Light and the High Light Pleroma accessory, which has the highest damage output of accessible skills at this point, but even that doesn't do quite enough damage to take out Trumpeter within three rounds. Kartikeya is great for this battle since he has Heaven's Bow, High Gun Pleroma, and Charge, in addition to carrying Debilitate. The combined damage output between them is enough to win this battle within three rounds. I also swapped in Nozomi for the final round since Trumpeter starts using Smile Charge more at low HP. She does solid damage against Trumpeter in addition to smirk removal, so this is one of the few times she's worth using.