i found him just outside the undead purgatory by the fog door but i dunno

So far one is certainly to appear near the second bonfire in Huntsman's Copse after you cross the small bridge, another is encountered randomly in the Lost Bastille near the bonfire at McDuff's Workshop, and another random encounter near the first bonfire in Earthen Peak.

one raided me in shaded woods in area with spooky pots, right next to the pit with basilisks

everywhere

Just found this fool in shulva

Everywhere.

I've experienced three Forlorn invasions thus far:

1. Huntsman's Copse- In the lower area across the bridge w/ the scythe-wielders.
2. Lost Bastille- Before crossing the bridge to Sinner's Rise.
3. Harvest Valley- In the small quarry just past the 2nd bonfire.

I've had Forlorn spawn at the exact same location.

You can almost guarantee a forlorn invasion traveling around the lost bastile while human. Where and when is the question.

He did that to me twice

He just came to the lost bastille! He's on a rampage!

Dear god

Oh no

NPC since I had the same encounter and was offline

There's two bosses there

They can invade even after the area boss(es) are dead, got invaded in The Forest of Giants when going for Giant souls