Chara asked why.

"'Cause it's tradition! And there's a funny story behind it." Asriel didn't even look up from the box of ornaments that had been hauled out, enthusiastically rummaging through them in search of the shiniest, prettiest baubles. He loved the golden ones the most, and Chara found themself helping to pick them out and separate them into a little pile.

That still didn't explain why. They pointed that out. Asriel laughed, missing the point of the question. He always did when Chara ventured to ask this sort of thing.

"Well you see, there's this monster who lives out in the woods outside Snowdin with these huge antlers. And a while ago, when they were just growing in, these monsters played a prank on him by putting decorations up on the ends."

"Which was not nice of them," Mom pointed out, while stringing a line of beads along the tree's branches. She never missed an opportunity to teach a lesson, which Chara didn't mind as much as when the grown-ups back on the surface would do it. The grown-ups there were awful. But Mom knew best.

That still didn't explain why.

"It was a little funny," Dad chortled. His deep voice was as soothing as the crackling fire he sat beside, without the sparky edge. "I had to keep a straight face while undecorating him. The whole time he kept ranting about the young generation."

Mom cracked a smile, one she tried and failed to hide from her kids. It was subtle, and maybe they were wrong... but Chara often got the opinion that the older monsters were funny to Mom and Dad. As though even some of the oldest monsters around were still like kids to them.

...that still didn't explain why.

"So from then on, right at the end of the year, the monsters in town started making these trees that look like him!" Asriel continued, beaming as he as he continued to comically overload the branch nearest to him. It sagged under the weight of holiday merriment. "It's fun! And the trees look really pretty."

It did look pretty. Fake and made of plastic, but pretty. Even prettier than the real trees Chara used to see on the surface. They'd be happy to never see another real tree again if this was going to be the replacement.

But... why...

"I think that about covers it, dear," Mom said with a giggle. "I think it's about time for the crown. Chara, are you ready?"

No.

But yes. By the Delta Rune, yes. There was nothing they wanted more.

Dad picked them up. The sensation of huge hands on them made them want to tense up and fight, but the warm surroundings were too peaceful, too friendly to make the thought stick. There could never be anything threatening about Dad. The most violent he could ever be was pulling up a weed.

They were lifted high, above the top of the tree itself. They eyeballed the tip, and carefully, lovingly placed the product of their and Asriel's afternoon where it belonged.

Asriel exclaimed with excitement. Mom remarked how perfect it was. Dad held Chara still until they had it just right, and then lowered them down so gently they didn't even make a sound when they landed on the creaky board floor.

Chara still didn't know why.

The holiday was obvious. Monster families loved each other. Monster families liked spending time doing fun things together.

...but why...

Why...

...why had they welcomed a broken little human right into the middle of it?

Chara didn't know why. But they were thankful. And they hoped, and prayed to anyone who was listening, that someday they could pay them back.

The Angel was perched atop the tree, lovingly crafted of paper and glue and every scrap of imagination Chara and Asriel had shared. Its wings dazzled with a million bits of glitter it didn't need, shining like a god made of rainbows. The wings were broad and cast a shadow over the room and the family that Chara was only too happy to share with them.

Chara didn't know why. But it didn't matter. They stopped asking, because no answer could ever explain the miracle of it. More importantly...

Chara didn't need to know why.

Chara was home.