Oh fucking really?
My man where Dem evidence
It's hard to show you in gameplay so instead, I will link to a DFO Wiki that has the quest showing him including the dialogue if you have The Knight:
wiki.dfo.world
Lost Warrior: "He's... coming..."
If player is a Knight: <player>: "Ah!"
Lost Warrior: "I'm lost. I don't know where I'm going, where I came from, or even who I am. Yes, everything has disappeared--no, they never existed. They're present, but they are not actually existing. Therefore everything is meaningless. Everything except for the fact that he's coming."
If player is a Knight: <Player>: "(This man...He's Carloso's Fragment! Which time slot are we in? I wasn't the only knight looking for Carloso's Fragments. There really has been someone else who's looking for Carloso...)"
If player is a Knight: Siran: "You're back. What do you think of him?"
<Player>: (I can't tell him about Carloso. Mm, then what should I tell him instead?) "Something really is off about him, but I couldn't figure it out. I didn't even know which point of time in the past we were in. But I don't think you should worry about him."
Siran: "Hm, I was sure something was off about him... Oh well, you think I shouldn't worry, so I won't. Thanks."
So yeah, it really is THAT GUY. The Metastasis is hard to actually point out but basically, it completely and utterly fucked up the World to such a fashion that before a retcon(or a change), it completely changed and shifted the timeline into an entirely different timeline entirely(Like Flashpoint).
After the retcon, we find out the original Timeline actually isn't gone after all and thus you can say instead, it literally CREATED an entirely new timeline and reseted it entirely.