Fallout 3

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Puce Moose

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Puce Moose

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About this mod

Mantis Labs. A forgotten corporation that slipped into obscurity after the War. Something within its dark walls has awakened...

Permissions and credits
The Mantis Imperative

v 1.08

Mantis Labs. A forgotten corporation that slipped into obscurity after the War. Something within its dark walls has awakened...


Fallout 3 is the only requirement. DLC and FOSE are NOT required.


Mart's Mutant Mod: Compatible with merged patch. If you use MMM, it is advised that you use FO3edit to create a merged patch. If you do not, the mods will still work together, but you may see venomlurks (from Mantis.esp) completely replacing mirelurks, instead of occasionally appearing with them.
FOOK2: Untested. No issues expected with Mantis.esp and Jello.esp. See issues for FWE below with balance modules, as similar compatibility issues will likely occur.
FWE: Untested. No issues expected with Mantis.esp and Jello.esp. *HOWEVER*, make sure to disable any "tougher stealth" or similar components, as it can make one section of this mod quite difficult, if not impossible.
  • It is recommended that you DO NOT load Combat.esp, XP.esp, Skillbooks.esp, or Medical.esp in conjunction with FWE, as their alterations will conflict with each other and may cause issues.

AfroSlayers Nuka-Cola Compatible. Depending on your load order, you'll either be more likely to see Afro-Cola (if AfroSlayers loads after jello.esp) or more Jell-O (if Jello.esp loads after AfroSlayers)


Extract the contents of the zip file into your Fallout 3 Data Folder and be sure to place a check mark next to the new .esp files before launching the game. This mod includes five .esps:

The Mantis Imperative - Mantis.esp (primary quest module)
The Mantis Imperative - Jello.esp (secondary quest module)
The Mantis Imperative - XP.esp (balance module)
The Mantis Imperative - SkillBooks.esp (balance module)
The Mantis Imperative - Medical.esp (balance module)
The Mantis Imperative - Combat.esp (balance module)

Modules are independent; you may enable as many (or as few) modules as you wish.

What does this mod do?

The Mantis Imperative is a multi-part mod that includes adventure and balance modules.

IMPORTANT: DO NOT BRING COMPANIONS WITH YOU INTO THE MANTIS LABS FACILITY Not only is the area not fully nav-meshed, but it will destroy the tightly-scripted events and tension that unfold in there. Leave them at home if you want a fun experience with this mod!

-- The Mantis Imperative --

The largest and central component of the mod. This is an adventure mod that leads you into the troubled past of Mantis Labs, a company that flourished before the Great War due to certain techonological advances pioneered by its scientists. Even though its employees are long since dead, something lives on within its walls...


* new adventure that takes the player to different areas
* four new monsters (one with a brand new model) that may also show up in the Wasteland
* three new weapons (two new models)
* new radio station with over two dozen lor-friendly songs, a dozen commericals, and lots of new voice work. Selections include Billie Holiday, Louis Armstrong, Benny Goodman, and many others. All songs have been verified to be either public domain or usable under a Creative Commons licesnse.

-- Jello.esp --

* adds a new NPC with new dialog trees, a new interior area, wearable jewelry, Jell-O, new recipes, new apparel items (with new models), and several new misc items to add spice to random finds around the wasteland.

* v 1.05 introduces seven new flavors of Nuka-Cola and a new mini-adventure centered around the new beverages.

-- XP.esp --

1) Doubles the XP required to gain a level.
2) Halves the XP obtained from lockpicking and hacking, and triples the exploration bonus (finding new map locations).
3) Flattens the XP curve for difficulty levels. There is no longer an XP penalty for easy difficulty nor an XP bonus for harder difficulties.
4) New perk automatically granted to the player based on Intelligence score that gives a small bonus to XP whenever XP is earned (to prevent those annoying 1XP kills.)

-- Skillbooks.esp --

1) Two skill books must be read to gain a skill point. To offset this disadvantage, the player will gain a small amount of XP whenever books are read.
2)Thirteen new perks. Players will gain a perk after reading ten skill books of a given type. The perk will of course relate to the skills granted by the book type read.
3) Some perks modified to be consistent with the skill book changes.

-- Combat.esp --

For those who like combat situations to be brutish, nasty, and short. All creatures and weapons deal 100% extra damage (not as extreme as it sounds; it makes for less occurrences of the classic "raider took three shots to the head before dying"). Player HP is reduced by about 25% (so make sure you are not heavily wounded before enabling this .esp) and ammo is much more scarce. Make each shot count!

-- Medical.esp --


By far the most drastic of the balance mods. These changes make the game considerably tougher. Primary features:

1) Stimpaks are more rare, more expensive, and now heal over a period of ten seconds instead of instantaneously. This makes combat have a more exciting feel with the ability to instantly heal to full health at any time no longer available.
2) Limbs require attention to be healed. Sleeping no longer heals a player to full health, and it does not heal injured limbs. The player must gather materials such as leather belts, compreseses, and surgical tubing in order to heal limbs (or visit a doctor.) Most wasteland doctors now sell the required healing supplies at more or less reasonable prices. The player has a first aid kit in the AID section that must be used to initiate limb healing. Stimpaks NO LONGER HEAL LIMBS.
3) All food changed. Most feed delivers much more radiation, but also better healing. Food will become your primary source of healing out in the wastes. As with Stimaks, food heals over time - but with a catch. Healing will be noticed only after digestion occurs, so expect to wait four to twenty seconds before experiencing beneficial effects. "Stacking" food items by eating multiple foods at once is discouraged, as it makes each food less effective.
4) Economy changed. The barter skill is significantly more important to bartering, and the player will pay more for things he buys, as well as receiving less for things he sells. When the player finds bottlecaps on corpses or in containers, he'll find approximately 50% less than before.
5) Item value on most items lowered. As a small bonus, the weight of many misc items has been reduced.

Nasty Zeta


This balance module is meant to make Mothership Zeta a *nasty* place, where death comes frequently to the player. Intended for those who think challenge should be generated by superior foes armed with superior weaponry, limited access to supplies, limited access to ammunition, and not simply a bucket of HP on enemies/huge numbers to present a challenge.

Best used with Combat.esp and Medical.esp from The Mantis Imperative, and FlatVats.esp from the NastyZeta file.

Primary features:
  • over 20 new alien food items with new meshes, textures, effects, and PiPBoy icons to find.
  • New Hydroponics bay to explore
  • ammunition availability drastically reduced
  • alien turrets now much more powerful
  • four new alien weapons (which the player can take and use against the aliens)
  • the player does not recover his or her inventory until the end of the adventure
  • fix to vanilla bug related to death ray disabling
  • drastic reduction in the effectiveness of alien biogel
  • several new abomination types, including cryo and burning abominations
  • new perk

ADCK for his great work on Vault 13. His architecture formed the bulk of my mod's interior exploration segments. Thanks!

Andersh for the excellent pig rat resource. Piggy would never have come to life without the help of his mod.

xm20k for his kind use of an excellent scoped 10mm pistol.

Casum for his fantastic work on Existence 2.0. His
his professional production and excellent
content inspired me to make my own stab at a station.

Kikaimegami for the necklace model from the always popular Kikais Equipment.

joe camel for the fine work on the tranquilizer pistol model.


v 1.08

  • reworked item removal script to hopefully address issues with other mods that add 'non-removable' content
  • adjustment to training module three for a small increase in ergonomics/survivability
  • manipulation of Piggy's package (so to speak) to improve his ability to sniff out the goodies in the final training module

  • Adjustment to several lists; Jell-O more uncommon now to prevent 'Jellopocalypse' takeovers of existing food availability
  • Adjustment to raider lists to increase the chance of finding a wide variety of things
  • The ability to sell necklaces and gold items to the ladies of Tenpenny Towers finally added. Over 80 lines of dialogue (not voiced) and dozens of speech challenges added.
  • two new gems with respective necklaces
  • one new Nuka-Cola limited-edition flavor

  • Note added regarding method to disable 'whistling' feature if it begins to grate instead of elate