In this game, some combinations of equipment or drugs give you either temporary (with hard debuff or no debuff at all) or permanent immunity to some damage.
I'll list the ones I'm aware of:
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Total immunity: Stoicism (requires both 7 Will and 7 Con) fully specced, being at less than 4% health gives you 36% damage reduction to every type. 15% more with Aegis (no debuff) and with the 50% from Morphine Shot it is over 100% damage immunity for 3 turns (4 for Statis). The debuff of Morphine Shot should kill you would you do nothing about it but with either a Super Health Hypo or Last Stand, you're safe; You can skip Aegis with 10 con and Conditioning but you'll still lose Electricity, Energy, Bio and Acid immunity without Aegis. Other combination can be thought with 12 CON and Tempered feats.
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Permanent bio immunity: It's new, it came with the bioinvestigative belt from Tchort Institute which provides 10% bio damage reduction. With Aegis (15%) and Iron Gut (75%), that's bio immunity 8 turns. Neither Aegis nor Iron Guts have cooldowns or debuff, so it's permanent as long as you have some on you, though the belt requires you to keep 20 AP to use them at some point. With high Mechanical DR it makes Spiders and Locusts from Expedition a joke. It's true too for most snakes except the infamous Wyrm.
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Permanent Mechanical immunity with a very specific set up:
So, mechanical damage reduction is not capped and can go to 100%, making the character immune. It is easily achievable with morphine shot, but the effect only lasts 2 turns and cannot be refreshed indefinitely. Luckily it is also possible to get to 100% without morphine:
- Lifting belt : 5%
- Ancient Rathound leather armor and tabis : 10%
- Conditioning : 24% (10% base, 9% from 14 CON, 5% from specialization)
- Stoicism : 36% (24% at 4% HP, 12% from specialization)
- Aegis : 15%
- Mushroom Brew : 10%
Permanent invulnerability to mechanical damage since Aegis does not have a cooldown. Yay!
A mechanical immune sledge build (AKA The immortal drunkard)-
Permanent mechanical component of melee immunity: https://rpgcodex.net/forums/threads/underrail-ironman.135885/Read here for details by Yaz on RPGcodex.
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Permanent Electric damage immunity: Obtained from the Tesla Armor and Galvanic foam in Metal Helmet and Boots.
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Explosion damage immunity: From the Blast Suit and Iron Head (respectively 85% and 16% damage reduction from explosions)
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Bio AND Acid immunity: From the well-known combination of the CAU armor, biohazard boots and either Grey Army Spec Ops helmet / Praetorians' Helmet / Coretech Helmet / Gas mask.
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Temporary immunity to Heat: Through Exothermic Aura (Psi abilities)
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Acid OR bio immunity: for snakes/ mutant dogs leather armor and association with either CAU or mentioned helmets in Bio and Acid Immunity.
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Thought Control immunity: Locus of Control provides it for a few turns. You need 10 Will and 75 points in Thought Control for it.
I wish to have a more exhaustive list though I think I'm not aware of anything else, I believe... If a similar topic already exists, please tell me, I'll just delete this one and post this on it (if relevant).
