Arknights: Endfield Si Build and Team Guide

Arknights: Endfield’s Danqingduh version launched on October 15, 2026, introducing the six-star Frost Support Operator Si. She provides Frost and Heat amplification, records damage with her Skill, summons Ink Souls, and uses Link Arts and Ultimate Arts to create additional bursts.

Although Si is classified as a Support Operator, she can create damage windows for the main DPS while also dealing respectable personal damage. Her value depends less on simply stacking Attack and more on understanding Brush Intent, Ink Souls, attachment consumption, and Link Arts.

1. Role and Core Mechanics

Si is a six-star Frost Support Operator who uses a Greatsword. Her main roles are elemental amplification, attachment synergy, and area damage. She works in both Frost and Heat teams.

Her Ultimate grants Frost and Heat amplification to the entire squad. Her Skill applies Brush Intent and records part of the damage dealt to the target. When the duration ends, or when Si uses Ink Release early, the recorded damage is converted into a burst. Ink Souls transfer damage and effects they receive to the original target.

After using her Ultimate, Si’s talent reduces the remaining Link Art cooldown of the Operator in position 01. Elite Promotion 1 reduces it by 10 seconds, while Elite Promotion 2 reduces it by 20 seconds. This affects the current remaining cooldown, not the permanent base cooldown.

2. Skill Breakdown

Basic Attack: Inspired Brushwork

Si performs up to five Frost attacks. Her Heavy Attack can cause Stagger, and an Execution against a nearby Staggered enemy deals damage and restores some Skill Energy. Basic Attack is usually the lowest upgrade priority unless Si is being used as a personal DPS.

Skill: Shared Landscapes

This Skill deals Frost damage and applies Immobilize and Brush Intent. It normally applies Frost Attachment, but changes to Heat Attachment when the Operator in position 01 has the Heat attribute. Damage dealt to a target with Brush Intent is partially recorded, then released as an area burst when the effect ends.

Ink Release costs 15 Skill Energy and summons an Ink Soul from a target affected by Brush Intent. Damage and effects received by the Ink Soul are transferred to the original target. Ink Closure costs no Skill Energy and can dismiss the Ink Soul early, making it move toward the original target and trigger the same burst.

Link Art: Prepared Masterpiece

Si summons an Ink Dragon to deal Frost damage. Her Link Art can be activated after an enemy’s Frost or Heat Attachment is consumed or absorbed. Teammates must therefore be able to apply and consume the correct Attachments consistently.

Ultimate Art: No One Is Allowed to Ruin the Mood

Si summons a giant Ink Dragon, deals Frost damage, and grants the entire squad Frost and Heat amplification. Her Ultimate also activates the cooldown reduction from her talent for the Operator in position 01.

3. Upgrade Priority

For a personal-DPS build, use: Link Art > Ultimate Art > Skill > Basic Attack. A common reference investment is 12 / 12 / 9 / 9.

For a main-DPS support build, use: Ultimate Art > Skill > Link Art > Basic Attack. Prioritize the Ultimate for team amplification and cooldown support, then upgrade the Skill to stabilize the Brush Intent and Attachment cycle.

At higher levels, the Skill’s damage-recording ratio can increase from 10% at level 9 to 13% at Mastery 3, while the Ultimate’s basic amplification can rise from 30% to 36%.

4. Weapon Recommendation

This is Si’s preferred weapon. It provides Knowledge, Frost damage, and Attack. Immobilizing an enemy increases the damage they take for 30 seconds, while Immobilizing an enemy or casting an Ultimate increases the damage of the next Link Art within 20 seconds. Time the trigger carefully because the Link Art bonus applies only to the next Link Art.

Legacy of Eternity

This is a reliable alternative. Applying Frost or Heat Attachment with a Skill increases Frost damage, and granting Spell Amplification to another squad member increases the squad’s Spell damage. It matches Si’s Skill and Ultimate mechanics well.

Herafinger

Herafinger is a usable transition weapon if you already own it. However, it relies more heavily on Frost Attachment. When the position 01 Operator is a Heat character, Si applies Heat instead, which may reduce the weapon’s compatibility.

5. Gear Recommendations

50-Type Yinglong DPS setup: 50-Type Yinglong Armor, 50-Type Yinglong Gloves, 50-Type Yinglong Beacon, and Biological Support Plate. The three-piece set increases Attack and improves the next Link Art after Skills are used, making it suitable for a more damage-oriented Si.

Longbreath support setup: Disaster-Relief Armor, Longbreath Energy-Conducting Gloves, and two Longbreath Rangefinders. This setup improves the damage dealt by other teammates after Si casts her Ultimate and grants amplification. It is better when Si mainly supports a Frost or Heat main DPS.

6. Recommended Teams

Si, Tangtang, Seiche, and Jie: a Frost and Spell synergy team. Establish Frost Attachment, maintain healing and amplification, and consume Attachment to trigger Si’s Link Art.

Laevatain, Si, Eltelada, and Jie: a Heat DPS team. Si applies Heat Attachment when Laevatain occupies position 01, Jie supplies additional Attachment, and Laevatain consumes Heat Attachment to enable Si’s Link Art.

Yvonne, Si, Jie, and Seiche: a Frost Attachment consumption team. Make sure Yvonne consumes Frost Attachment rather than only natural Attachment, or Si’s Link Art will not activate.

Bele, Si, Jie, and Seiche: a high-Frost-Attachment team. Build enough Frost Attachment to meet Bele’s conditions, consume it with her Link Art, then chain into Si’s Link Art.

Tangtang can replace Seiche in some teams for additional Attachment or Spell-related synergy, but this reduces healing. Make sure the team can survive before giving up a healer.

7. Version Rewards and Top-Up

Si’s “Renewal of All Things” Special Search remains available until November 5, 2026, at 11:59 server time. The Seven-Day Sign-In event grants five Special Search Permits. Si’s Combat Drill and Danqingduh activities also provide Originium, equipment, and other rewards. Claim free resources before planning additional pulls.

If you need more Originium or want to continue pulling for Si or her weapon, visit the Kardz Arknights: Endfield top-up page. Check the product contents, server requirements, account information, payment amount, and delivery instructions before completing a recharge.

8. Final Summary

Si is a six-star Support Operator who combines team amplification, Attachment synergy, and personal damage. Choose her weapon, gear, and skill order according to whether she supports the main DPS or acts as a secondary damage dealer. Most importantly, build a team that can reliably apply, consume, or absorb Frost and Heat Attachments.