Temple of Ranma's Sailor Senshi Seifuku

I want something that describes two people who are very alike personality-wise. The closest that I can think of is "two peas in a pod," but that seems more focused on their appearance being similar, or the two people in question don't seem to be seen separately often.

In Cat's Cradle, Vonnegut used the word "duprass". It was a stronger version of what you ask, though.

Pretty much.

I just remembered "cut from the same cloth." As a title, though, it's kinda...

My sister and I are very much this way, so I'll be interested in seeing what eventually rises to the top.

Unless I find something that reads and looks better, the latter. Another problem with it, though, is that it may give the impression that the story's about Rarity. Of course, anyone who knows her and Ranma would know that they have little in common.

I don't think that Ranma and Rarity have all that much in common, except maybe fore being vain.