Remember to back up files before changing them https://forums.elementalgame.com/420611
As with all core file changes you'll need to start the game using a similar shortcut:
"C:\Program Files\Stardock Games\FallenEnchantress\FallenEnchantress.exe" -localdataonly
Open CoreUnits.xml and remove all instances of
<GameModifier>
<ModType>Unit</ModType>
<Attribute>UnlockAction</Attribute>
<StrVal>BuildImprovement</StrVal>
<StrVal2>Outpost</StrVal2>
</GameModifier>
also open CoreSpells.xml and remove
<SpellDef InternalName="ArcaneMonolith">
<DisplayName>Arcane Monolith</DisplayName>
<Description>Creates an Arcane Monolith on the map which extends your Zone of Control.</Description>
<Image>S_IneluctableVision_Painting.png</Image>
<IconFG>S_ArcaneMonolith_Icon.png</IconFG>
<IconColor>10,10,117</IconColor>
<CanStack>0</CanStack>
<SpellType>Strategic</SpellType>
<SpellClass>Terraform</SpellClass>
<SpellTargetType>NeutralGround</SpellTargetType>
<SpellResourceCost>
<Resource>Mana</Resource>
<Amount>30</Amount>
</SpellResourceCost>
<GameModifier>
<ModType>Map</ModType>
<Attribute>BuildWildImprovement</Attribute>
<StrVal>Outpost_ArcaneMonolith</StrVal>
</GameModifier>
<ValidTerrainCategory>City</ValidTerrainCategory>
<ValidTerrainCategory>Forest</ValidTerrainCategory>
<ValidTerrainCategory>Land</ValidTerrainCategory>
<AIData AIPersonality="AI_General">
<AIPriority>0</AIPriority>
</AIData>
<HitSoundFX>Spell_Enchant_02</HitSoundFX>
<SpellDefEffect>
<EffectName>S_AuraofGrace_Particle</EffectName>
<LocalPosition>0,0,0</LocalPosition>
<EffectScale>.75</EffectScale>
<EffectDelay>0</EffectDelay>
<SnapToTerrain>1</SnapToTerrain>
</SpellDefEffect>
</SpellDef>