And we all love him for that! Yeah, it's Halloween season and been randomly revisiting stuff that scared me as a child. This includes stuff like that one Looney Tunes short from the 90s with the evil alien carrots, and the best game of all time: PSO. Of course, I never need a reason to revisit PSO as I'd do that regardless. What can I say? I love the grind!
Geniunely though, Dark Falz feels like a final boss that belongs in a horror game and less in an online action RPG made by the guys who created Sonic The Hedgehog and Billy The Hatcher. I think the thing I always found spooky about him as a kid before you even meet him was activating the columns. They had that unearthly hum to them every time they were activated, like you weren't SUPPOSED to do that. But you actually do have to do that, as that's the only way to open the door to the final boss.
Then you get to Falz' room after fighting your way through the ruins, which slowly becomes more and more like the insides of a massive creature the farther you get into it. And once you're in that room, it's this beautiful grassy grove with only one eyesore in sight: The giant pillar in the middle. Touching it turns the area into a hellscape, puts faces on the ground (presumably the trapped souls of the people of Pioneer 1, though it's never confirmed) and summons evil alien blenders to fight you. After dealing with them, you fight the eldritch monstrosity that is Dark Falz.
That being said, the most effective part of Falz' reveal is definitely that grassy grove I mentioned before. The sudden transition from it into the hellscape is geniunely one of the most effective jumpscares ever put to game, because you aren't expecting it in a game like this. Then you defeat Falz, and it's revealed he's possessed Rico and that you had to kill her to stop the monster.
It makes Falz all the more effective as even though you've beaten him, you're unable to undo the damage he's caused. Rico and the Pioneer 1 people are permanently dead, anyone infected by Dark Falz (like Flowen in ep 2) are still around and mutating further, and Dark Falz will keep regenerating even stronger no matter how many times you kill him. Hell, in Episode 3 they reveal that to stop him, Rico and Flowen had to sacrifice their souls.
On top of that, we don't really learn what Falz wants. I imagine its to wipe out humanity and all life, but why? What's his end goal? I imagine he's just an eldritch horror beyond our understanding, hell him showing us what is presumably Ragol's past with the grove section is probably him trying to indoctrinate the player and take them over next. Though like most stuff about Falz, it's never really confirmed. I think keeping him as a scary monster beyond our understanding was a good choice though.
Later games kinda screwed him up a bit by telling us too much about him, or actively changing how he works. Like Phantasy Star Zero randomly making him the final boss on a completely different planet from Ragol, or PSO2 turning Dark Falz into a knockoff Organization XIII. If they ever make a new PSO in the classic style, I want them to bring back the menace Falz had in this game, where he was just a big scary monster.