The name Xulchilbara may be made up of two words; Xulchil (a corruption of the Aztec Xochilt), meaning flower, and the Japanese Bara, meaning rose.
Meaning flower, Xolchilt is also present in the name of an Aztec goddess, Xochiquetzal. She was worshiped as a goddess of fertility, childbirth, pregnancy, and a protector of young mothers, among other things.
It's name may also derive from Xōchiyāōyōtl, or Flower War. Captives from these battles were often times sacrificed to sustain Aztec religious rituals.
Another possibility, though connected more to Silent Hill rather than the Red God, arises in the concept of the Mayan underworld, called Xibalba. It's presented as being rife with trials and traps, much like Silent Hill and the surrounding areas.
"Crimson Ceremony"
Speak.
I am the Crimson One.
The lies and the mist are
not they but I.
You all know that I am One.
Yes, and the One is I.
Believers hearken to me!
Twenty score men and
seven thousand beasts.
Heed my words and speaketh them
to all, that they shall ever be
obeyed even under the light of
the proud and merciless sun.
I shall bring down bitter vengeance
upon thee and thou shalt suffer
my eternal wrath.
The beauty of the withering flower
and the last struggles of the dying
man, they are my blessings.
Thou shalt ever call upon me and
all that is me in the place that is
silent.
Oh, proud fragrance of life which
flies towards the heart. Oh Cup
which brims with the whitest of
wine, it is in thee that all begins.