I'm talking about Dimension PK here.

I won't go into full details, but all I'm gonna say is PK knew Milia at a younger age. It's up to you to decide his childhood based on the hint I gave to you just now.

Oh yeah, Dimension PK always refers Milia as a beautiful sexy lady. He claims that she has better looks than Yukari.

On the other hand, the original PK (the one with time) compares Milia to Yukari as an old gap hag.

Both PK's compare Milia to Yukari, which is really funny imo.