Ghost Song

To unlock this achievement you’ll need to visit Gili at 4 moments throughout the game and defeat an optional boss related to the questline. Each moment can be accessed in sequential order after returning a component, starting with when you’ve returned none. You can find the exact locations over at https://drive.google.com/drive/folders/1-cWtLR4MTxVPkU8L_-k2... if you’re unsure of the described location.

Location 1 (0 components returned): Found right where the game starts in Lupoto. I believe she shows up here once you’ve reached the Crash Site.
Location 2 (1 component returned): Found at the very top-left room of Ekman’s Crossing. You can get here by jumping over the Big Bot at Stoffbloom.
Location 3 (2 components returned): Found at the bottom of the middle room of Sap-Stone, on the way to Ekman’s Crossing. I don’t know if Devilwink - the boss found in this room - needs to get moved to the top floor for the interaction to happen but you don’t have to kill her beforehand.
Location 4 (3 components returned): Found at the top of Sap-Stone. She’ll ask you to convince a bounty hunter named Hector to spare her. You can find him at the left side of where the same room where the region’s Big Bot is located (to the right of the room you’re at after going up to Ekman’s Crossing). Persist trying to convince him and he’ll eventually fight you; due to his simplicity I won’t go over how to fight him. It should be noted however that fleeing Hector produces an alternate ending to the questline that might not unlock the achievement. Defeat Hector then return to Gili for a weapon and this achievement.

So for this you need the Ankle Spikes. Gili has a wonderful story about regret and sentience. I usually found her in the green area to the right of base camp or in the blue area thereabouts. Make sure to loop the whole rectangle.
She will find a gun as the second to last interaction. And then move one level north and mention Hector. He can be found in the extreme northeast of the map..

I wont spoil more but this definetly left me conflicted. Thanks for playing this wonderful game.