Sunday — Honkai Star Rail Character Guide

Overview

Premium action advance support who enables hypercarries and summon-based DPS with 100% action advance, CRIT/DMG buffs, and Energy restoration. Specializes in summon synergy and multi-turn buff uptime. SP-neutral at baseline, SP-positive with signature Light Cone.

Action advance support who grants allies and their summons extra turns via 100% Action Advance on Skill, paired with stacked CRIT buffs and DMG% increases. Ultimate designates an ally as "The Beatified," granting CRIT DMG scaling from Sunday's own CRIT DMG stat plus Energy restoration. Manages a 130-Energy Ultimate cycle across 3 actions to maintain permanent Beatified uptime, with SP neutrality achieved by recovering 1 SP when using Skill on a Beatified target.

Key Mechanics

• Buffs provided: 30% DMG (Skill, 80% for summon owners), 20% CRIT Rate (Talent, 3 turns), CRIT DMG equal to 30% of Sunday's CRIT DMG + 12% (Ultimate, 3 turns). All buffs are single-target on the designated ally and their summon.
• Ultimate uptime is critical — without Beatified active, Sunday loses SP recovery from Skill and the CRIT DMG buff. Requires 130 Energy every 3 actions. With signature LC (6 Energy per ability use) + ERR rope, this is guaranteed. Without signature, needs ERR rope + ERR planar + getting hit.
• Summon synergy: Action Advance from Skill also advances the target's summon. The 50% additional DMG boost applies only to summon owners (total 80% DMG). This makes Sunday uniquely powerful for Lightning-Lord, Numby, Netherwing, memosprites, and Souldragon.
• SPD tuning: -1 SPD build (134 with 135 carry) enables double actions per cycle. Hyperspeed (160+) drags the carry to Sunday's SPD value, allowing the carry to drop SPD investment entirely. -1 SPD is more actions overall but requires precise tuning.
• Energy restoration from Ultimate (20% of target's Max Energy, minimum 40) is wasted on characters without Energy mechanics (Feixiao, Acheron at E0, Castorice). The CRIT/DMG buffs still apply, but a significant portion of Ultimate value is lost.

Best DPS Pairings

Ashveil (S), Mydei (S), Phainon (S), Aglaea (S), Saber (S), Argenti (S), Blade (S), Yunli (S), Jing Yuan (S), Dan Heng • Imbibitor Lunae (S), Dan Heng (S), Misha (S), Yanqing (S), Silver Wolf LV.999 (A)

Investment Priority

1. E1 — Priority target — 40% DEF ignore for summons is transformative, 16% for non-summons significantly boosts damage output across all DPS
2. LC S1 — Signature guarantees 3-turn Ultimate rotation and provides SP economy, critical for maintaining buff uptime
3. E2 — Adds 30% DMG to Beatified state plus SP restore on first Ultimate, major damage and economy upgrade
4. E4 — Removes all Energy concerns with 8 per-turn generation, enables flexible stat building

Best Relics

Recommended: sacerdos-relived-ordeal with lushaka-the-sunken-seas

Stat targets: SPD 134 (-1 build) or 160+ (Hyperspeed), CRIT DMG 180-220%+, Energy Regen 119.44-124.44%+ (without signature), Effect RES 30%+

Main stats: Body: CRIT DMG · Feet: SPD · Sphere: HP% / DEF% · Rope: Energy Regen

Important Notes

• Requires 3-turn Ultimate uptime for SP-neutral economy — without signature LC, need ERR rope + ERR planar + getting hit to maintain it
• Energy restore wasted on characters without Energy mechanic (Feixiao, Acheron at E0, Castorice)
• Cannot advance Harmony characters with Skill — they get DMG buff but no action advance
• -1 SPD build requires precise tuning — 1 SPD slower than DPS, or rotation breaks entirely
• Hyperspeed build (160+) requires very high SPD investment and can break team rotations
• E6 CRIT Rate buff can be wasted if DPS already has 100%+ CRIT Rate from relics