<Genre conventions are generally a poor source of guidance, yes. I'd be happy to explain things to your parents as well. It depends on whether you think they'd be supportive of your activities as a Celestial Guardian, or mostly try to get in the way.>

<Well, what are the activities of a Celestial Guardian?>

<It depends a lot on what you want them to be. You can live a mostly normal life while fending off the inevitable attacks of Naya and her various evil minions, or you can go seek them out and foil their plans before they get close to you. Once we've explored the potential of your powers some more, there may be other things you want to do with them as well, depending on your ambitions and what you turn out to be good at. What would you say are your main goals in life?>

<Man, I dunno, I'm not a very ambitious person. Who's Naya and why is she going around inevitably attacking things? And where is she getting evil minions?>

<I'm afraid I don't know much about her motivations, beyond that she's a fan of mind control and places very little value on terrestrial life. She was imprisoned in a pocket dimension to prevent her from attacking the world directly, but she continues to act through susceptible minds.>

<...well that sucks. Can we, like... stop... her? Nuke her pocket dimension or something? Nuking the pocket dimension is maybe overkill but I am not a fan of mind control.>

Neither cats nor telepathy are particularly good at smiling, but a smile is conveyed nonetheless. <Neither am I. I don't know how to destroy her, yet, but with enough work and magical research it may prove possible. And you will be able to find other Guardians as well, one for each planet in this star system, who may also be able to help.>

<...are they going to help or are some of them also mind control criminals? Or do you not know?>

<They are reincarnations of the Guardians I once knew. I don't remember everything, but if any of them were evil I'm sure I would have remembered that. 

<...fair. Okay.>

She contemplates all this for a few moments.

<...let's not introduce you to my parents just yet, but I think it's an option if hiding you from them gets really inconvenient.>

Minerva nods. The train approaches April's stop.

April leads Minerva to her house and sort of awkwardly stands in the street contemplating cat concealment.

<How good are you at climbing, can you sneak in my bedroom window if I go inside and open it?>

Minerva scopes out the drainpipes and window ledges and says, <Certainly,> then goes and lurks in a shadow and awaits window-opening.

Window access is forthcoming within about five minutes of April entering the house.

Then Minerva will leap gracefully inside and assume the loaf position on April's bed like she lives here.

<I shall start at the beginning. When sapient, which is to say ensouled, life evolved on this planet, unknown thousands of years ago, this began a process which created the being known as the Earth Guardian, who by direct action and indirect magical influence created the other Celestial Guardians corresponding to Mercury, Venus, Mars, Jupiter, Saturn, Uranus, Neptune, and for reasons I cannot recall Pluto. Celestial Guardians are much harder to kill than humans, have the transformation ability you have already used, can travel anywhere in the solar system with no need for protective equipment, and can learn to create magical artifacts. Each one also has certain unique abilities; your Moonlight Clarity incantation falls into this category.>

What a helpful exposition loaf.

"Where does the Lunar Guardian come into it, am I piggybacking on Earth somehow or an I my own celestial body or what?"