Ivory Bastion

A flying survivor who deploys into an immobile missile fortress. Fight on the move to refill your missiles, then hold a position to build drones and earn permanent upgrades for the run.

The Seraph design pairs white armor and black machinery with blue engines, a throne-mounted cannon, forward-facing missile banks and two vertical warhead launchers. Includes custom models, animations, HUD, effects and female AI dialogue.

How to play

• Mobile: move quickly, evade attacks and use Needlefire to replenish your shared missile stockpile.
• Siege: deploy near the ground, aim freely and hold your position with shields, drones and heavy weapons.
• Engineering: press V to view upgrades. Purchases and drone changes require siege mode; the key is configurable and shown on the HUD.
• Switch forms with Shift. Deployment takes 0.8s, packing takes 0.25s, and switching has a shared 6s cooldown. Deploy within 6m of solid ground.

Flight follows your aim while moving. Space rises; release movement to hover. Look down and move forward to descend. Sprint increases flight speed.

The modular HUD keeps missiles and thruster fuel above skills, fabrication immediately left of the combat panel, and Seraph/Aegis defenses above health. The fabrication module shows income, progress toward your next upgrade, and your configured Engineering key, while keeping ally and drone readouts clear.

Resource bars use teal for fuel, coral for missiles, orange for heavy-shot progress, and green for fabrication. Shield hexagons are reserved for the defense gauges.

The values in this guide are the default balance; hosts can customize them in Mod Options. Base stats: 100 health (+30/level), 12 damage (+2.4/level), 1 health regeneration/s (+0.2/level), 0 armor. Mobile speed is 14m/s, or 20m/s sprinting. Damage percentages below use your damage stat, before crits, items and enemy defenses.

Mobile abilities

Siege abilities

Skyfall uses its own ammunition, so you can keep firing your primary throughout. A cluster means three or more enemies in one blast. Warheads spread their damage when possible; a lone enemy can receive all ten. No enemies in range preserves the charge.

The stockpile holds 40 missiles and starts with 30. Reload is 1 missile/s in siege, 0.25/s while mobile, plus ammunition earned by Needlefire. Heavy missiles cost one stockpile missile each.

Proc coefficients: Needlefire and regular missiles 0.6; Ion Lance, heavy missiles and Skyfall 1.0; drone bullets 0.5.

Seraph Shield and survival

Seraph Shield is its own resource, separate from health and item shields. Its white-and-blue hexagonal gauge sits directly above normal health, with an independent yellow-and-black Aegis Barrier gauge above it. Both follow the native health bar's tilt; level, XP and buffs have their own space above them. Matching status icons identify both pools. Three soft, low beeps warn when your Seraph Shield breaks; a quiet electrical buzz marks the start of natural recharge. Both are local and respect your audio settings.

Damage passes through item barrier → Aegis Barrier → Seraph Shield → item shields → health. Seraph Shield refills in 2s after the delay; barrier-only hits let its timer continue. Healing and native item-shield refills do not recharge it. Its reduction protects Seraph itself and also fortifies Aegis Barrier while Seraph has charge. Item barrier, item shields and damage overflowing into health do not receive Seraph's reduction.

Shield capacity follows your final max health, including item pickups and late stat bonuses: 100 → 200 max HP increases mobile Seraph from 15 → 30, or siege Seraph from 50 → 100, before upgrades. Existing shield damage is preserved when capacity grows. Aegis grants 40% of your current max health when cast; an existing barrier keeps its remaining points and decay.

Packing instantly refills the mobile shield. Deployment preserves existing shield damage. Siege also heals 1% max health/s after 3s without damage.

Aegis and charged Seraph Shield stack for 67.5% reduction on both defense pools, before armor. After Seraph Shield breaks, active Aegis retains its own 35% reduction. Its gold hexagonal sphere remains independent of the blue sphere.

Drones

Drone damage uses your current damage stat; health is set when constructed. The first permanent Bulwark arrives after 2s; vacant slots rebuild on a 15s timer. Packing docks survivors without healing them.

Legion II lets you change every unlocked drone slot, including the first. Your choices and upgrades persist between stages.

Fabrication and upgrades

While deployed, earn 14 Fabrication/minute idle or 35/minute in combat. Nearby enemy kills, including ally kills, add 0.25 normally, 0.75 for elites and 2.5 for bosses. Production stops with the run timer. Mobile form does not earn Fabrication.

Press V to buy upgrades in siege mode. Each branch costs 60 / 140 / 300 Fabrication for its three ranks. Currency and purchases last for the entire run.

Cooldown items work with abilities and fuel refill. Extra secondary stock adds fuel capacity and Aegis charges; extra special stock adds separate Blue Shift and Skyfall charges. These bonuses do not create missiles.

Installation and multiplayer

Install through Thunderstore Mod Manager or r2modman with dependencies enabled. All players and the host need the same mod version.

Requirements are declared in the package: BepInExPack, RoR2BepInExPack, HookGenPatcher, Risk of Options, and R2API Core, ContentManagement, Prefab, Language, RecalculateStats and Networking.

Local ZIP imports do not download libraries automatically; install the requirements first. Custom missiles support normal damage/item procs, though mods requiring native projectile objects may not recognize them.

Settings

• Open Settings > Mod Options > Ivory Bastion for every config option: audio, volume, Engineering key and gameplay balance.
• Balance categories cover base stats, every ability's damage, ranges and cooldowns, shields, missile capacity/reload, Fabrication, upgrades and each drone's role. Defaults preserve the previous release's balance.
• Gameplay changes apply to the next run. In multiplayer, everyone automatically uses the host's balance. Your own saved settings are preserved for when you host.
• Audio and controls apply immediately. Enable Mod Audio mutes all Ivory Bastion sounds on your computer, including other players' cues. Volume defaults to 0.65; Engineering defaults to V.
• Settings are also saved in BepInEx/config/com.yuiki.ivorybastion.cfg.
• Character audio currently supports Windows. Aegis dialogue has a 30s repeat cooldown.

0.32.0

• More reliable multiplayer abilities. Requests survive pauses, important skills get priority over a backed-up primary queue, and abilities queued around a form change get enough time to activate.
• Fixed skills being ignored after taking control of an existing body. Client and host control handoffs now preserve request delivery.
• Barrier hits pause passive hull repair correctly. They still let Seraph Shield recharge behind the barrier, as intended. Shield amounts, healing and damage reduction are unchanged.

0.31.0

• Restored Aegis and Seraph defense stacking. While Seraph has charge, it also fortifies Aegis's yellow barrier. With active Aegis, the two give 67.5% damage reduction before armor, or 73% with Hardening. Separating the defense pools had accidentally removed this protection from Aegis.
• Seraph Shield follows your final max health. Health pickups, level-ups and later stat bonuses now update its capacity in both forms. Doubling max health doubles shield capacity; ordinary stat updates cannot refill damage already taken.

0.30.0

• Seraph Shield and Aegis Barrier get their own defense pools and gauges. Their charge stays readable above health, even when item effects change the normal health bar. Aegis absorbs damage before Seraph.
• Shield protection follows the damage it absorbs. Seraph's damage reduction protects its own points, and Aegis still stacks with it. Hits absorbed by barrier let Seraph keep recharging behind it.
• A clearer HUD for the fortress. Fuel is teal, missiles are coral, heavy-shot progress is orange, and Fabrication is green. Combat resources sit above skills, with Fabrication alongside them so ally and drone readouts stay clear. Upgrade progress and your Engineering key are always visible.
• Quiet cues keep you informed. Three low beeps warn when Seraph breaks, and a soft electrical buzz marks recharge. The buzz stops if the shield takes another hit. Both cues are local and follow your audio settings.
• Fixed flight and unresponsive skills after installing a local update over the official release. Updated the RecalculateStats requirement to 1.7.0.

0.22.0

• Added all config settings to Risk of Options, including volume and the Engineering key.
• Added 137 gameplay settings covering survivor stats, abilities, shields, missiles, production, upgrades and all four drone types. Existing balance remains the default.
• Balance changes apply at the start of the next run. Multiplayer clients automatically use the host's settings without changing their own saved config; audio and controls apply immediately.

0.21.0

• Bulwark focuses on defense: armor 20 -> 40, gun damage 75% -> 25% per second, firing range 25m -> 15m. Health, taunt, pull and stun are unchanged.
• Gunner focuses on damage: sustained damage 100% -> 200% per second, range 40m -> 50m. Fires 80% damage every 0.4s. Health 200% -> 150% of yours; armor 20 -> 0.
• Repairer now chooses injured health instead of wasting healing checks on full-health allies with depleted shields. Interceptor is unchanged.
• Engineering now shows each drone's role. Shortened the mod description and changelog around gameplay and current stats.

0.20.0

• Restored siege camera fading when armor obstructs aim, while keeping normal views visible.
• Improved multiplayer skill delivery with retries and duplicate protection. Transformations finish independently of their animation; outdated updates cannot roll the model or resources back.
• Added a safe boost timeout and let Engineering purchases go through without interrupting attacks.

0.19.0

• Corrected dependency installation guidance and added a companion dependency profile for local installs.

0.18.0

• Reduced excessive siege camera fading and improved detection around gaps in the model.

0.17.0

• Added 120m Ion Lance lock-on, a target marker, and reliable locked hits without double damage from the blast.
• Improved silo interiors and added siege camera fading.

0.16.0

• Skyfall now prioritizes clusters > bosses > elites > ordinary enemies, spreading damage before repeating targets.
• Set blast radii to 5m regular / 10m heavy / 15m Skyfall. Damage remains 130% / 450% / 800%.

0.15.0

• Innate shields now reduce damage by 50% in both forms. With Aegis, siege reaches 67.5% total reduction.
• Hardening gives 55% shield reduction, 40% Aegis reduction, and 73% combined.

0.14.0

• Heavy battery missiles now fire every 8th shot, or every 6th with Warhead System.
• Reduced boost fuel to 3s base / 5s upgraded.

0.13.0

• Made regular and heavy missiles more visible and increased Skyfall damage to 800% per warhead.
• Temporarily increased blast radii; their current values were set in 0.16.0.

0.12.0

• Restored enclosed Skyfall launchers with slimmer housings and consistent missile proportions.

0.11.0

• Reduced rear-launcher bulk and clipping around the fortress legs and missile banks.

0.10.0

• Added the raised throne, rebuilt rail cannon and two vertical Skyfall launchers.
• Ion Lance now explodes in an 8m radius without damaging beam victims twice.

0.9.0

• Replaced mobile and siege thrusters with flowing blue plasma exhaust and softer ground effects.

0.8.0

• Refined both Seraph models, flight animation, shields, weapon effects and HUD artwork.

0.7.0

• Improved client transformations with host confirmation and clear failure messages.

0.6.0

• Fixed disappearing models and primary attacks lost when multiplayer updates arrived together.

0.5.0

• Added the local audio switch to Risk of Options.

Early releases (0.1.x)

• Introduced both forms, Engineering upgrades, configurable drones, shared missiles and Fabrication.
• Developed the Seraph models, blue explosions, shields, flight effects and AI dialogue.
• Added run-persistent progression, item interactions, shield recharge rules and multiplayer support.