Obviously, this poem is all about Ren!

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Some might say he's quite small
Or has a heart of ice,
But with that spike he stands quite tall,
And is sorta, kinda nice.

Sure his hair is strange,
Quite funny I think so too,
Better get out of the firing range,
If you tease him, he will kill you.

January first.
Two celebrations on that day.
Let's hope his anger won't burst,
New Year's and his birthday!

His birthday wish? A party!
And that everybody is dead.
And his laugh will be hearty,
On the plate? Horo-Horo's head.

HAPPY BIRTHDAY, REN-KUN!