Looking to clear all three endings in IS-5 quickly and efficiently? You’ve come to the right place! In this Arknights IS5 Endings Guide Unlocking All Endings & Boss Tips, we’ll go over the requirements to unlock each ending and provide strategies for the boss fights.
Arknights IS-5 Endings Guide Unlocking All Endings & Boss Tips
Ending 1: The End
How to Unlock
This one is the easiest to get—just play through your run normally! When you reach the final prophecy node on Floor 5, select option AE, and you’ll automatically get this ending.
Things to Avoid
On Floor 2, don’t pick the first option on the prophecy node. Doing so will push you toward Ending 2.
Don’t select the second option at a Lost and Found node, or you’ll trigger Ending 3.
Boss Fight: Fremont – Lighter of Mines
Stats: 100,000 HP, 1250 ATK, 1500 DEF, 80% RES, 0% Elemental Resistance
Major Mechanic: If an operator is defeated or retreated, they get trapped in a Sarcophagus of Exile until destroyed.
Key Strategy: Avoid letting Fremont stack his Improvised Defense (which reduces damage taken by up to 90%). Keep him engaged in combat to prevent this!
Best Operators: Opion is a great choice as his Skill 3 lets him bait Fremont’s charged attacks while dealing damage and avoiding teleportation in Phase 2.
Ending 2: Twin Crowns
How to Unlock
First, complete Ending 1 in a prior run.
On Floor 2, select the first option on the prophecy node. You’ll get Pure White Petals and Wordless Deed (which take up 10 toil limit).
At the end of Floor 2, merge them into the Pledge of Babel (which increases DP cost for all operators).
Final prophecy node on Floor 5: Choose the first option, “Declare the King’s True Names.”
Boss Fight: Incest Teresis & Teresa – The Black-Crowned Lord and Sage
Phase 1: Teresa is invulnerable and continuously charges a devastating AoE attack (scaling up to 500% damage!). Teresis is tough with high DEF and RES, but his damage resistance depends on his distance from Teresa.
Phase 2: A death timer of 500 seconds (8 min 20 sec) starts. Teresis stops moving but becomes stronger, while Teresa continues attacking.
Key Strategy: Use specialists to separate Teresa and Teresis to minimize their synergy. The Ten Rings collectible can make the fight easier.
Best Operators: High burst DPS, ambushers to handle Wither Devours, and strong sustain to handle Teresa’s AoE.
Ending 3: City of Angels
How to Unlock
First, complete Ending 1 in a prior run.
Progress as normal, but before beating the Floor 4 boss, find a Lost and Found node and pick the second option to get Prophet Horn.
This turns your next refreshed node into a Prophecy Node. When you find it, pick the first option to get Time and Light.
Finish Floor 5’s boss fight and move to Floor 6, where the final boss awaits.
Boss Fight: Patriot – Holy Gun Knight
Phase 1: He has 15,000 HP, 3,000 ATK, 5,000 DEF, and 80% RES. His attacks buff operator ATK but also increase damage taken by 50%.
Phase 2: Revives at full HP, gains ranged attacks, and summons Guardian Bulwarks, which reduce incoming damage.
Key Strategy: Hold Patriot in place and chip him down. Protect Guardian Bulwarks, as they help mitigate damage.
Biggest Threats: FS Portals that permanently remove your last deployed operator—either block them or let them leak strategically.