First, get yourself a text editor.
simple as that.
Remember to make a copy of any files you plan to you edit so you can restore your empires if the file gets corrupted or if you mess up and can't figure out how to fix it again.

Now, find your user_empire_designs txt file. It should be in C:\Users\Username\Documents\Paradox Interactive\Stellaris

Open it.


This is where your custom empires are stored.

Now you just need to find the empire you want to edit.

Find the part where it says graphical_culture and city_graphical_culture.













Change the text inside the quotation marks to any of these:

graphical_culture (for ships):
- fallen_empire_01
- fallen_empire_02
- fallen_empire_03
- fallen_empire_04
- fallen_machine_empire_01
- swarm_01
- extra_dimensional_01
- extra_dimensional_02
- extra_dimensional_03
- ai_01

Note that most of these does NOT have textures for all types of ships, and will use the mammalian shipset for the ships it doesn't have textures for.
Usually this means only the science ship has special textures.

city_graphical_culture (for cities):
- fallen_empire_01
- fallen_empire_02
- fallen_empire_03
- fallen_empire_04
- fallen_machine_empire_01
- preindustrial_01
- industrial_01
- solarpunk_01

To change the room of your empire, find the part where it says room
Then change the text inside the quotation marks to any of these:
- personality_fallen_empire_cyan_room
- personality_fallen_empire_red_room
- personality_fallen_empire_blue_room
- personality_fallen_empire_machine_room
- personality_fallen_empire_yellow_room
- personality_fallen_empire_teal_room
- shroud_room
- ship_room
- swarm_room
- technosphere_room
- shroudwalkers_room
- salvagers_room
- no_video_feed_room
- mercenary_enclave_room
- galactic_emperor_room
- galactic_custodian_room
- ethic_spaceship_room
- crisis_room
- enclave_trader_room
- enclave_artist_room
- enclave_curator_room
- caravaneer_home_room
- paragon_azaryn_room
- paragon_keides_room
- paragon_skrand_room
- pre_ftl_victorian_room
- pre_ftl_medieval_room
- pre_ftl_modern_room
- pre_ftl_ancient_room
- runic_room
- slaver_room
- solarpunk_room

Find the part where it says species, and then find the name list



Then change the name list (in this case, MOL2 which is molluscoid 2) to any of these:

- AI
- Cybrex

After this, if you want to edit, do NOT click on the name list button, as this will reset the name list to aquatics 1

To change your empire's flag to something a bit more special, find the "empire_flag" part:Then change the part marked with red to: special
And the part market with blue to: the_shroud.dds
Now you should be able to go into the empire creators flag section for that empire and be able to choose between a lot of different special flags.

The enclave flags, at least those from the leviathans DLC, are not in the special category, and so if you want to access those, you'll need to change the part marked in red to "enclaves" and the part marked in blue to "enclaves_flag_artist.dds".


The same is true for pre-ftl flags, for which you'll need to change the part marked with red to "pre_ftl" and the part marked with blue to "preftl_atomic_age"

Country flags have nothing to do with actual flags. Instead, they are strings of text that have an effect on the game.
While some may have big effects and could cause major disruptions to normal gameplay and/or break the game in various ways, those listed here should be fine and shouldn't cause any unintentional side effects to happen, or if they do they are very minor.

First, make a new line anywhere and write flags = { } like this:


Inside of these brackets, add any of these, with a space between each:

- irassian_world_found (enables the secrets of the Irassians artifact action)
- yuht_world_found (enables the secrets of the Yuht artifact action)
- vultaum_world_found (enables the secrets of the Vultaum artifact action)
- cybrex_world_found (enables the secrets of the Cybrex artifact action)
- last_baol_system (enables the secrets of the Baol artifact action)
- last_zroni_system (enables the secrets of the Zroni artifact action)

- edict_masters_writings_politics (adds an event edict)
- edict_masters_writings_diplomacy (adds an event edict)
- edict_masters_writings_philosophy (adds an event edict)
- edict_masters_writings_war (adds an event edict)
- edict_improved_work_environment (adds an event edict)
- edict_renewable_energy (adds an event edict)
- edict_super_sensors (adds an event edict)
- nuumismatic_visualization (adds an event edict)

- finished_brainslug_chain (Gives some of your leaders the brainslug trait. Should also prevent anyone from getting the brainslug event)

- composer_covenant_rank_1 (Gives access to the sanctum of the composer and adds half the composer's bonus to telepaths)
- eater_covenant_rank_1 (Gives access to the sanctum of the eater and adds half the eater's bonus to telepaths)
- instrument_covenant_rank_1 (Gives access to the sanctum of the instrument and adds half the instrument's bonus to telepaths)
- whisperers_covenant_rank_1 (Gives access to the sanctum of the whisperers and adds half the whisperer's bonus to telepaths)

- has_built_or_repaired_megastructure (Enables you to take the galactic wonders ascension perk without making a megastructure yourself)
- democratic_khanate_flag (Allows you to build habitats)

- artist_building_patron
- bought_waste_reprocessing_center
- nuumismatic_shrine
- divine_algorithm
- city_of_bones_completed

- relic_last_baol_activated (using both of these gives you a one-time use of nu-baol life seeding)
- not_activated_baol

- bunkbeds_ready (grants access to a one-time-use planet action)
- tupperware_ready (grants access to a one-time-use planet action)
- atmospheric_deodorizer_ready (grants access to a one-time-use planet action)

- fallen_empire_machine (Makes ancient mining drones friendly)

- fallen_empire_1 (Chance of becoming a scion overlord if any empires use the scion origin)
- fallen_empire_2 (Chance of becoming a scion overlord if any empires use the scion origin)

- limbo_downloaded (enables the limbo project when you get the appropriate tech)

- harvested_voidspawn_dna (Gives the ability to add the voidling trait when you genetically ascend)
- harvested_dragon_dna (Gives the ability to add the Drake-scaled trait when you genetically ascend)
- harvested_tiyanki_dna (Gives the ability to add the Tiyanki trait when you genetically ascend)
- harvested_radiotrophic_dna (Gives the ability to add radiotophic to your pops)

- toxoids_7060_A (Add a knight job to the orders keep)
- toxoids_7090_a (Orders keep adds 15 stability and unlocks herald knights. Knights also produce 5 amenities)
- toxoids_7011_a (Knights produce more unity)
- toxoids_7040_a (Knights produce more unity)
- toxoids_7130_c (Knights produce more unity)
- toxoids_7011_b (Knights produce more research)
- toxoids_7040_b (Knights produce more research)
- toxoids_7130_b (Knights produce more research)
- toxoids_7220_a (Knights produce more research)

- constitutional_immunity (Makes you no longer be in breach of galactic law, at least until someone revokes your immunity)

- killed_guardian (makes your supremacist and militarist factions happy)
- worm_tomb_ending (Enables you to colonize tomb worlds without angering the spiritualist faction)
- suppress_vanilla_factions (Prevents factions from forming)

- studied_stellarite_infestation (Makes you immune to the eat star operation)
- cannot_steal_enigmatic_tech@ (Replace @ with a number from 0 - 40, then repeat this until you have all the numbers from around 0 - 40. This should prevent most empires from performing the steal technology operation against you)
- fotd_seperatist_country (No empires can conduct espionage against you)

- dark_forest_achievement (If you have the fanatic purifier civic, this flag should give you +1 civic slots once the game starts)

Note: I have not tested the following flags (all the way down to the bottom of this chapter, not just the next "block" of flags), but they should work as described, in theory.

- sold_pops_for_crystals (Should make you very unlikely to get the 'sell pops for crystals' deal from the caravaneers)
- bought_numistic_cruiser (Disablest the numistic cruiser deal)

Note: For the following flags, if you add more than 1, only the one highest on this list will work.
- fleet2deal5 (Numistic caravaneers will always offer governor)
- fleet2deal6 (Numistic caravaneers will always offer to buy pops for crystals)
- fleet2deal2 (Numistic caravaneers will always offer to sell pops (This may not work correctly for gestalt empires, except for rogue servitors))
- fleet2deal7 (Numistic caravaneers will always offer to sell a numistic cruiser)
- fleet2deal8 (Numistic caravaneers will always offer to sell a numa's breath)
- fleet2deal11.b (Numistic caravaneers will always offer to sell exotic gasses)
- fleet2deal11.c (Numistic caravaneers will always offer to sell alloys)
- fleet2deal12 (Numistic caravaneers will always offer to sell minor artifacts)

Note: For the following flags, if you add more than 1, only the one highest on this list will work.
- fleet1dealcost1 (Veangilum trium will always charge a Specialist pop for its products)
- fleet1dealcost2 (Alloys)
- fleet1dealcost3 (Unity)
- fleet1dealcost4 (Society research)
- fleet1dealcost5 (Science ship)
- fleet1dealcost6 (Worker Pop)

Note: For the following flags, if you add more than 1, only the one highest on this list will work.
- fleet1dealproduct1 (Veangilum trium will always sell bunkbeds)
- fleet1dealproduct2 (tupperware)
- fleet1dealproduct3 (Athmospheric deodorizer)
- fleet1dealproduct4 (consumer goods)
- fleet1dealproduct5 (___ modifier)
- fleet1dealproduct6 (___ modifier)
- fleet1dealproduct7 (energy credits)


Example:
By adding the flags "irassian_world_found", "yuht_world_found" and "vultaum_world_found" you can research the secrets of these precursors from the start of the game!

Find the part where it says civics:

Then change your civics to any of these:
- civic_galactic_sovereign
- civic_galactic_sovereign_megacorp
- civic_psionic_sovereign
You can only have two civics, even if they give you additional civic slots. You can, however, add more civics once you can reform your empire.
You can also pick two of the same civic.

Find the part that says ruler

Then add an extra trait="trait_id"

You can find the leader traits in:

Governor Traits:
C:\Program Files (x86)\Steam\steamapps\common\Stellaris\common\traits\00_governor_traits.txt

Admiral Traits:
C:\Program Files (x86)\Steam\steamapps\common\Stellaris\common\traits\00_admiral_traits.txt

Scientist Traits:
C:\Program Files (x86)\Steam\steamapps\common\Stellaris\common\traits\00_scientist_traits.txt

General Traits:
C:\Program Files (x86)\Steam\steamapps\common\Stellaris\common\traits\00_general_traits.txt

Any class:
C:\Program Files (x86)\Steam\steamapps\common\Stellaris\common\traits\00_generic_leader_traits.txt

Special traits (any class):
C:\Program Files (x86)\Steam\steamapps\common\Stellaris\common\traits\00_special_leader_traits.txt

You can add destiny and veteran traits if you want, basically any trait as long as it's the correct leader class and isn't a starter trait.