New events

[crisp rain]

This mod is absolutely amazing, but i think new behaviors with a lot of unpredictability is something that could add onto the creepiness factor, i really dont know how he behaves in the nether nor the end, but in my time playing, him showing up only to disappear almost immediately is yes very scary but can get stale, id say have him break ladders, replace blocks youve placed down, aswell as breaking nether portals, could also have new sounds, voices that creep from the dark or whispers during the players sleep, a thing it could also do although disabled by default could be using popups on the actual computer when the player isnt fighting mobs or in dangerous situations (of course to avoid immersion being broken by bad timing) with very creepy mewssaging, flashing text (the bugged/corrupted look you can get on texts, i have no clue how to actually write that stuff) but yea these are some ideas

[round elk]

Yoooooo I definitely agree with the last one.

[surreal cargo]

So to mention, the breaking Nether portal, Hmmm.. =u=
Good idea, very similar to unlighting nether portal but imo its actually better because it does unlight but also makes it where the player needs to place another block of obsidian down..

The pop-up idea as well I dont think can be done since the mod is a datapack and the thing with FtF is LES wants to keep them both in parity meaning not one will have unique features when the other cant have it..
To explain why I mention the datapack as well is datapacks can from what I know only effect the game itself and not anything that is outside of it, even the crash mechanic requires something more ingame then just closing the game itself otherwise a suggestion from long ago could have been possible which was instead of the instance of minecraft closing if we cant just get kicked to the menu but that isnt possible due to it only being able to effect the game itself..

I am pretty sure LES is actually planning on adding more sounds..

Having him break/replace blocks is pretty cool but it would have to be kinda rare and also off by default..

Voices from the dark as a sound would be pretty cool as well ngl..

I would say though have something popup with the bugged messages sounds pretty cool as well, I dont think it would be necessarily a popup itself unless it could something to do with the hud?.
Maybe thats how the popup mechanic could work is through the hud.

Sorry for unorganised Essay message.. XD
I hope this doesnt seem nitpicky, I do like a majority of ideas and have upvoted it myself.. ^u^

[oblique vector]

Datapacks are essentially just glorified command block programming yeah, no popups possible

[surreal cargo]

Interesting but true way on putting it.. ^u^

[austere haven]

perhaps like a /title thing? for a split second, you see one of herobrine's messages flash up on screen, FNAF "It's Me" style (just obviously... not fnaf), and its maybe somehow transparent so that it's barely visible?

[crisp rain]

not title

id say

chat message

but have the crypitc messages also lead something more

perhaps a secret

but he sends them through the /tell command

[unborn folio]

action bar, so you couldnt look back to see it

[crisp rain]

GOOD IDEA

ima be honest tho, the mod really isnt scary most of the time and i got everything turned to the max

i think hacving things ramp up with time with perhaps a way or 2 to calm it down if you need could be a great idea

[surreal cargo]

Although would be a cool idea for implementation, I am pretty sure I saw something about it not being possible for an actual message to be sent looking like Herobrine sent it..

I am remember something about a Fake Message overlay type thing but if I remember correctly a dev or staff said wasnt possible..

Although I do have an idea for something which could be possible..
What if a "sound" played but quiet enough for the player to not hear it but the sound would be labelled "It's Me" or whatever in the subtitles?.

Might make this a seperate suggestion depending..
Need to ask something in questions first.. ^u^