How to get Perman Item

[Blub]

I finished the main story and got three Perman Items only, I was wondering if anyone can tell me where can I get the fourth one.
I've been running the Explorations for each stage regularly and I still couldn't find the fourth one. Couldn't unlock the last character from the Universe because of this. :(

[Rutia]

I don't remember exactly, but the fourth last one, I suspect it on a grounds. so you have to expand area and then look around it. (I believe you already have that secret tools for that)
Sometime you have to remove your property(buildings) to shows it up. Good luck. In addition, Look for the left side in particular.... But as I said, I don't remember exactly, so don't trust me...