Honkai Star Rail: The Best Sunday Build

Sunday is the latest addition to Honkai: Star Rail, bringing exceptional support capabilities that enhance teams—especially those featuring summon-based characters. However, his utility extends far beyond that, making him a top-tier Harmony unit capable of boosting CRIT Rate, CRIT DMG, Energy regeneration, and turn efficiency.

In this guide, we’ll provide an overview of Sunday’s abilities, explain how he functions in different team compositions, and recommend the best builds to optimize his performance. Whether you’re using him alongside familiar-wielding allies or integrating him into more flexible team setups, this guide will help you maximize his impact on the battlefield.

Sunday Overview

Name: Sunday
Rarity: 5-star
Element: Imaginary
Path: Harmony
VA: Otsuka Takeo (JP)

Stats at Level 80:
• HP: 1242
• ATK: 640
• DEF: 533
• Speed: 96

Sunday is a limited 5-star Imaginary Harmony unit, designed to be one of the strongest supports in Honkai: Star Rail. His 100% Action Advance skill applies to both characters and their summoned entities, making him an ideal partner for summon-reliant units like Jing Yuan and Topaz. However, his buffing potential extends beyond summon-based teams, making him a more flexible and SP-efficient alternative to Bronya.

Sunday provides invaluable team-wide benefits, including CRIT Rate and CRIT DMG boosts, Energy regeneration, and turn manipulation, all while maintaining SP efficiency. His only real drawback is his high Energy cost, which means teams need to account for his ultimate uptime. Additionally, the current roster of summoning characters is somewhat limited, meaning he won’t always be utilized to his fullest potential—though this is likely to change with future updates.

Pros & Cons

Pros:
✔ 100% Action Advance skill for allies and summons
✔ SP-positive compared to other Harmony supports
✔ Powerful buffs, including CRIT Rate, CRIT DMG, and Energy regeneration
✔ Ideal for summoning-based characters but works in any DPS-focused team

Cons:
✖ High Energy cost requires careful team-building
✖ Lack of summon-based characters to fully maximize his kit (for now)

Sunday redefines support roles in Honkai: Star Rail, offering one of the most well-rounded and future-proof buffing kits in the game. Whether paired with summon-reliant DPS units or standard hypercarry teams, he effortlessly amplifies their effectiveness, making him a top-tier pick for any account.

Best Light Cones for Sunday In HSR

1. A Grounded Ascent (Best Option)
• Effect: After using his Skill or Ultimate on an ally, Sunday regenerates 6 Energy, and the targeted ally gains a “Hymn” stack for 3 turns, stacking up to 3 times. Each stack increases their DMG dealt by 15%. Every two instances of Sunday’s Skill or Ultimate use restore 1 Skill Point, improving team SP efficiency.

2. But the Battle Isn’t Over (Great Alternative)
• Effect: Increases Energy Regeneration Rate by 10% and regenerates 1 Skill Point when using an Ultimate on an ally. This effect triggers once every two Ultimates. When Sunday uses his Skill, the next ally taking action deals 30% more damage for 1 turn.

3. Past and Future (Best Free-to-Play Option)
• Effect: When Sunday uses his Skill, the next ally to act deals 16% increased damage for 1 turn.

Which One Should You Choose?

If you have A Grounded Ascent, it is by far the best option as it enhances Sunday’s Energy regeneration, Skill Point management, and overall support capabilities. However, if you don’t have it, But the Battle Isn’t Over is a strong alternative thanks to its Energy Regeneration and DMG buffs. For F2P players, Past and Future is a solid budget choice that still provides a meaningful DMG boost to the team.

Sunday Best Relics In HSR

To optimize Sunday’s support potential and ensure consistent Ultimate uptime, the best relic combination is a 4-piece Sacerdos’ Relived Ordeal with 2-piece Lushaka, the Sunken Seas. This setup enhances his buffing capabilities while helping with Energy Regeneration, making his rotations smoother and more effective.

The 4-piece Sacerdos’ Relived Ordeal set boosts Sunday’s overall support utility, reinforcing his role as a high-impact buffer for CRIT-based teams. Meanwhile, the 2-piece Lushaka, the Sunken Seas planetary set increases Energy Regeneration, which is crucial for Sunday to keep his buffs and turn manipulation active without downtime.

For stats, Sunday benefits most from CRIT DMG on the Body, Speed on the Feet, HP% or DEF% on the Phanar Sphere, and Energy Regeneration on the Link Rope. These stats ensure that Sunday not only enhances his allies’ damage but also cycles through turns efficiently.

When looking at substats, Speed should be the highest priority to help Sunday act more frequently and keep his buffs up. CRIT DMG is also valuable since it directly enhances the effectiveness of his buffs. Effect RES% helps prevent him from getting disrupted, while HP% and DEF% provide extra survivability to keep him on the field longer.

By focusing on Speed, CRIT DMG, Energy Regeneration, and Effect RES%, Sunday can maintain his buffs effectively while ensuring he stays active in battle.

Sunday Skill Priority

Unlike some characters who rely on a single ability to maximize their effectiveness, Sunday benefits from leveling all of his key skills equally. His Skill, Ultimate, and Talent are all crucial to his role as a support, so they should be upgraded simultaneously to ensure he provides the best buffs and utility to his team. His Basic Attack holds the least importance and can be left for last.

For Major Traces, the best order of priority is A2 first, as it provides the most impactful benefits, followed by A4 for additional utility, and finally A6 to round out his kit.

Priority Order:
• Ultimate = Talent = Skill → These should be leveled together, as they all contribute to Sunday’s ability to buff, generate Energy, and manipulate turn order.
• Basic Attack → Least important and can be leveled last.

Major Trace Priority:
• A2 > A4 > A6 → A2 offers the most significant improvement, followed by A4, with A6 being the final upgrade.

By investing evenly in Sunday’s core abilities, he will be able to maintain high uptime on his buffs, enhance his team’s damage potential, and keep his Energy Regeneration smooth for consistent Ultimate usage.

Conclusion

Sunday is one of the most versatile and powerful Harmony supports in Honkai: Star Rail, offering a unique mix of CRIT buffs, Energy regeneration, and turn manipulation that makes him an invaluable asset to many teams. Whether he’s paired with summon-based units like Jing Yuan or integrated into hypercarry setups, Sunday brings unmatched synergy and utility.

By equipping the right Light Cone, Relics, and stats, Sunday can maintain consistent Ultimate uptime, provide high-impact buffs, and ensure his team operates at peak efficiency. His ability to advance allies’ actions, boost CRIT Rate and CRIT DMG, and enhance Skill Point management solidifies his role as a top-tier support.

For players looking to maximize their damage dealers, Sunday is an exceptional addition who will elevate any team composition. With the right build and investment, he will undoubtedly remain a staple support unit for future content in Honkai: Star Rail.