Okay, I’ve decided to make a list detailing the status of all the islands in the Atlantean Invasion AU. I’ve made this thing based on what I’ve read from the comments on my own post along with the original post by Mirage, though some things might be a bit inconsistent. If you have any suggestions, feel free to leave 'em in the comments!
Dawn Island - Very low Atlantean presence thanks to the constant storm. Occasionally a lost sailor washes up there.
Mango Isle - Very low Atlantean presence, largely due to nobody living there.
Elm Island - Low Atlantean presence, though Edward Kenton would probably be fighting off lost sailors occasionally.
The Jaws - Low Atlantean presence thanks to the Pelion Rift and the fact that the Jaws make it difficult for large ships to travel through. However, places like Redwake and the Spire Bandits’ Camp would probably become more fortified to fend off attacks from the occasional Atlantean sailboat/caravel. Shura would probably be fine, though he’d likely leave the Silent Ire.
Frostmill Island - Low Atlantean presence thanks to the constant chill. Some survivors and frost brigands might still live there, though they’d definitely have to fight off Atlanteans every now and then.
Darkpine Isle - Low Atlantean presence, largely due to nobody living there.
Goso Jungle - Low Atlantean presence, though Souvella would probably leave.
Thorin’s Refuge - Low Atlantean presence, though Thorin would probably leave.
Limestone Key - Low-Moderate Atlantran presence, largely due to some coming from Palo Town nearby.
Palo Town - Moderate Atlantean presence, town would likely be wiped out early in the invasion.
Whispering Caverns - Moderate Atlantean presence, survivors would likely try to drain the flooded mines and turn it into a safe zone.
Whitesummit - Low Atlantean presence due to the cold. Blackwater grotto criminals/Assassin’s Guild members would likely try and fight off the Atlantean hordes.
The Stepstones - Moderate-High Atlantean presence. They’d occasionally try to climb up to reach the sky islands, but would be knocked back down before they reach the top. As such, they’d all be surrounding the base of the mountain.
Silverhold - No Atlantean presence thanks to the efforts of the Grand Navy. GN would likely maintain a full lockdown of the place, forbidding anyone to enter or leave.
Harvest Island - Low-Moderate Atlantean presence. Sarlovéze would probably leave, though he’d also be able to kick any Atlanteans who approach into the whirlpools.
Munera Garden - Low Atlantean presence. Sir Gavin definitely won’t be fixing the place up anytime soon.
Forest of Cernunno - Moderate-high Atlantean presence. Cerynx and the Cult of Greenwish would probably try and fight off any Atlanteans who set foot on the island, though they would probably be overwhelmed over time.
Sailor’s Lodge - Moderate Atlantean presence, would likely be overrun shortly before the Atlanteans head for Ravenna.
Fort Talos - Low Atlantean presence. The surface of the fort would be abandoned, collapsing for another reason instead of the player, but survivors would turn the dungeons into a refuge. However, they are unaware of the fact that General Argos, buried under rubble yet still alive due to mutating into an Atlantean, still dwells within.
Shell Island - High Atlantean presence. The surface of the island would be covered in Atlanteans, but the ancient ruins there would become a safe zone. The people there would likely live in constant fear of being discovered.
Sandfall Isle - Very low Atlantean presence due to the heat and the fact that nobody lives there.
Ravenna - High Atlantean presence. Most of the island would be overrun, but survivors would hide inside of Mount Caesar. Prince Revon, Julius, and King Calvus would be here as well.
Wind-Row Island - Moderate Atlantean presence. The Wind-Row bandits would use the huge ravine to their advantage in order to launch ambush attacks on unsuspecting Atlanteans.
Blasted Rock/Cassia Bay - Very low Atlantean presence. The sandstorm would likely deter most Atlanteans from even setting foot on the island. Would probably become a safe zone for desperate survivors.
Mount Othrys - No Atlantean presence. Atlantean ships would probably crowd the base, but likely wouldn’t be able to get into the Titan Caverns. Some survivors would likely try and turn the island into a safe zone, though the sheer amount of ships means one would need a fleet to get past them.
Akursius Keep - Very high Atlantean presence. Atlanteans would likely be drawn here due to the insanity effects of the place reminding them of their homes in the Dark Sea.