She found herself
Thinking of her childhood
And something
That made her heart ache
Idly, she started conversing
About a canary
Before angry tears welled up
She was prodded more
And she got more upset
But still willing to talk about it
She found her canary dead in its cage
She knew who dispatched it
She stated her father gave it to her
And it was one of the last things he gave her
Before it was taken away
So mercilessly
"Why didn't she kill me, too?!"
She stated that, by that point,
She had no family
Her father was taken away
But, years before, he was sister was gone
She assumed them dead
And then her canary was taken away
A hapless victim
Back then, she was stoic
She had no other choice but to be
But, now, she was crying
She wondered why she wasn't killed, too
She felt guilty for having survived as long
For what she'd become
She stated in, simple terms,
Her canary's slaying cemented a cold fact
A fact that
She was alone
She was rambling on
About how cruel things truly were
And how she wished
She was killed, too
Before stopping momentarily
Calmly saying
"Oh, yes, she did kill me, too, in a way."
Before going on yet again
And then stopping
Her eyes were wide
A 1,000-yard stare of realization
She remembered that day
"Ain't I worth staying alive for, Sis?! Ain't I...?!"
She had almost made a horrible mistake
Some time ago and this was a further realization
She was not the only victim
Of her own madness
Her father was taken away from her
She lost her canary but she still had a gift
The one who saved her
She fainted from the heartache
Waking up in her sister's arms
She couldn't say anything besides,
"I'm so sorry..."
Authoress Note: One thing to note is that Satsuki has a bird motif, though it's subtle, but it's definitely there, with her "Ask not the sparrow how the eagle soars", her analogy of a sandpiper, the fact that she's usually somewhere high-up, and the fact that, at one point, Ragyo keeps her in a cage (which looks an awful lot like one of them antique birdcages).
Likewise, much of her situation calls to mind of being trapped, in which case, in a subtle shoutout to Trifles, I came up with scenario that she's had a pet canary, a gift from Souichiro. Like the canary, Satsuki was "caged", with the only difference being is that the canary was killed, and Satsuki is alive, though some parts of her had "died".
Why a canary and not something like a sparrow or Daurian redstart? IDK, a canary made the most sense.
—Amoridere.