Cousins in Dozens - a Young Wizards musebox/chatbo

1. Earth knew himself to be the youngest, a long time before he came to understand how he was the youngest. And, even with a Moon to accompany him, much of the time he still felt alone.
Except for... something. Some feeling, that came over him when he stared aimlessly out at the darkness too long. A warm feeling, like another atmospheric layer but better.
He wished it had a name.

2. Eventually, the others tried reaching out, actually talking with him - but, he noticed, never when the Sun was looking. The first was Jupiter - enormous, yet self-conscious, aware of just how small the rocky planets were and unwilling to harm any of them.
Earth found himself awash with awe and respect, counterbalancing fear. Surely Jupiter - or his close partner, Saturn - could do no wrong...

3. Then there was Mars - quick to talk about the nature of having Life, those strange little one-celled organisms striving around in Earth's oceans. These conversations brought about feelings that didn't make sense - worry, sadness - but all at a distance.
As if they weren't his. The warmth was like that feeling, in a way, but more pleasant. Somehow meant for him.

4. Mercury spoke to him before Venus did; Earth chalked that up to Venus having an entirely different orbit from everyone else. Mercury seemed... a little out of it, really (and he couldn't blame him, since the Sun kept an eye on him all the time), but still generally good-natured. And he talked to his Moon separately, which made the other smile. And that was good too, right?
But when Venus spoke, something seemed wrong. Like the other planet - almost his size exactly - felt he shouldn't be speaking to Earth.
Perhaps the answer laid in the fourth emotion-that-wasn't-his: distaste. Not avoidance, just a detached sense of distrust. That sense extended - much more strongly - to the Sun. So when he wanted answers, he went to Mars or Jupiter instead.
He was told that all planets - and rocky planets in particular - came from the crashed remains of previous generations of rockies. That some of them remembered those other planets, and mourned them. So they're mourning, and they feel... guilty? Maybe? But who do they miss?
Earth was sure there was more to it, but none of the other planets (and he never dared ask the Sun) ever yielded a name.

5. In his dreams, at least, he didn't have to feel alone. There were gestures of friendship - and more, the source of that strange warmth discovered in full and experienced in its truest depths - and it could just be the three of them.

Wait... three?

Luna tentatively called his name; regretfully, Earth pulled away to find out what his Moon wanted.
But he'd find his way back the next time he went to sleep. He never liked feeling alone.