Willie
"Who named these concepts was a researcher of sorts... But a Heartless is how it's described: a being without a heart... Hence they go forth attacking creatures with Hearts to gain them." 

She'd explain and wave her left hand slightly and a flash of white light appeared on the ground, summoning a Dusk. 

"And a Nobody is the body left behind... Which is an extremely rare chance of occurring. I presume the name came rather than *No Body* Rather the derogatory term of something less than a person. It is a taxing naming convention I know... Anyway. I did come to ask more of your disposition though in the state you are, those questions will be moot. Not like you can feel them anymore to orate your emotions without guessing."
Mabel
*Xion gives a small hum of consideration at these words before shrugging* "I'm used to covering up for feeling hollow and empty inside constantly. This is no different. So now that I'm apparently one of you, what's with the cloak? It's all spooky and mysterious though it doesn't look very suited for a place like this." *She says as she casually gestures at the fact that this place is a hot, humid nightmare*
Willie
"The cloak is used to protect aginst the darkness when using the Dark Corridors... Each use eats away at ones heart until they become a Heartless. So I was slightly surprised that you kept using them..." 

She would say and raise her hands to her hood, grabbing it by the sides and pulling it down to reveal her face.
Michael
"Albeit that function is of little purpose to us... The world we come from it rains all the time and these are primarily raincoats." 

As Uxyr spoke, she shook her head, fixing her hair back to the way she liked it so it didn't bother her.
Mabel
"I'm strong but I'm not exactly versed in the other worldly mystical mumbo jumbo whatever of the... Multiverse, I guess? I'm just an absurdly talented magic student from Twilight Town. Dark Corridors, Keyblades, traveling worlds, yadda yadda, so on and so forth. You get the idea. Those are all outside my realm of knowledge. Also..." *She pauses, unabashedly staring at Uxyr's face* "Don't know how many people have told you this but you're an absolute knockout~" *And there comes the flirting. Even as a Nobody, she doesn't change one little bit.* 
"On a different note... Is there any way I could get one of those cloaks? I have... Ideas, to say the least. And I like the way they look."
Michael
"If you wish to join our cause, I can explain those concepts in more detail. I assumed you were feigning ignorance of these things before with how adept you were with using the darkness and a keyblade." 

Uxyr would say and then stared blankly about being called a 'knockout', that was a word she never heard used in such a context. 

"I have knocked people out before, yes. Though back at the topic at hand... Our goal is to gain hearts once more. I did not explain it before since such a feeling of emptiness and sociopathy would be lost and pointless to explain. If you join, you will get a black coat just like mine and the others."
Mabel
*Xion shrugs* "Yeah, sure. I'll join. Just hope you don't mind if I keep up my studies cuz I intend to do that as long as I can. Shouldn't interfere with your own cause too much if at all. Also if by 'gather hearts', you mean continue blowing up Heartless, sure. It's not too different from what I've already been doing."