Unlock the full potential of your Sub-DPS with Impermanence Heron, which not only amplifies the Resonance Energy of the equipping character but also boosts the ATK of the next character to take the field. This skill is a powerhouse, dealing a whopping 300%+ total Havoc DMG. For Moonlit Clouds, it remains the top choice, though the Nightmare version offers a slightly different approach with its Midnight Veil sonata effect, tailored more towards Havoc Sub-DPS characters.

Elevate your Sub-DPS game with Hecate, the premier echo for coordinated attacks. By increasing ATK for the current resonator when critical hits are landed, Hecate ensures your team stays on the offensive. Moreover, its echo effect summons blades that can attack even when the character is off-field, providing continuous pressure on the enemy.

Experience the thrill of summoning Nightmare Inferno Rider in the heat of battle, as it unleashes a formidable attack that can quickly turn the tide. This echo's ATK boost lasts for 15 seconds after skill activation, and its skill can deal up to 270% damage. Beyond combat, it also serves as a rapid traversal method in the overworld.

With Nightmare Crownless, deal massive damage with each summon, totaling 270% damage. The skill's charge feature allows for multiple uses, making it a versatile tool in your arsenal. This echo's capabilities make it a valuable asset in various combat scenarios.

For Electro DPS characters, Nightmare Tempest Mephis stands out as one of the top echoes. It's crucial to determine whether your Resonator scales off Resonance Skill or Resonance Liberation; if it's the former, Tempest Mephis is the way to go. Additionally, access to Empyrean Anthem sonata effects makes it compatible with coordinated attack Sub-DPS characters, offering flexibility in team composition.

Another top contender for Electro DPS is Nightmare Thundering Mephis. This echo is tailored for Resonators that scale off Resonance Liberation, making it a powerful choice for specific team builds. Understanding your Resonator's scaling is key to maximizing Thundering Mephis's potential.

As a primary 4-cost echo for Gusts of Welkin and Windward Pilgrimage, Reminiscence Fleurdelys grants a significant Aero DMG Bonus, with an additional 10% bonus if worn by Aero Rover. It's also pivotal for Ciaccona as an Aero Erosion enabler and forms the definitive echo set for Erosion DPS, Cartethyia. Notably, it provides a brief time-slowing effect upon use, allowing for damage to be dealt freely within a small window.

The Lady of the Sea is a primary 4-cost echo for Aero Crown of Valor, distinguished by its ability to group enemies with its echo skill, making it excellent for tackling mob groups. Since the echo skill is summon-type, it ensures uninterrupted combos, providing seamless combat experience.

While Nightmare Lampylumen Myriad excels at providing passive Glacio DMG Bonus and Coordinated Attack DMG buffs, its skill deals 270%+ Glacio DMG. However, it's less versatile than Hecate in most scenarios, primarily because not all resonators that deal Coordinated Attacks benefit from Glacio DMG Bonus.

For characters utilizing Spectro Frazzle, such as Zani and Phoebe, Capitaneus is the main echo. It offers an unconditional Heavy Attack DMG boost, making it superior to Nightmare: Mourning Aix. Despite being a valuable asset, farming it can be challenging due to its 3-cost rarity.

Focused on Sub-DPS in Havoc teams, Nightmare Impermanence Heron may lack flexibility but packs a punch with its 300%+ total Havoc DMG skill. The normal variants might find more utility in non-Havoc team compositions, suggesting a degree of adaptability despite its focused design.

For the best HP-scaling supports, Fallacy of No Return is the premier Rejuvenating Glow echo, particularly noteworthy for its synergy with Shorekeeper, the current top-tier healer. A unique feature allows for rapid charging of Concerto Energy by holding the echo button, all while enabling resonators to act freely as Fallacy delivers a flurry of punches.

Those running the Frosty Resolve sonata effect will find Sentry Construct to be the best echo available. It not only deals significant damage but also provides echo bonuses without needing to be summoned, making it a consistent and powerful choice.

Tailored for Augusta, The False Sovereign offers both Electro DMG and Heavy Attack DMG Bonus, standing out as the only 4-cost Echo in Crown of Valor. Its transform-type nature means some time is dedicated to dealing damage with it, but the stat bonus is automatically applied once equipped, requiring no echo skill activation.

Although Lioness of Glory is somewhat niche, being specifically beneficial for Lupa, it holds value as a 4-cost echo in Flaming Clawprint. Its effect shines when used by Lupa but is less impactful on other units, making it a targeted investment for those building Lupa.

Currently, Nightmare Kelpie is recognized for its role in the 44111 echo configuration of Cartethyia as a secondary 4-cost echo. The buffs it provides, although somewhat underwhelming, affect both Glacio and Aero DMG Bonuses. Notably, it lacks a sonata effect that directly benefits Glacio characters, despite offering them buffs.