The fire invisible

No one saw it burn,
no one felt its warmth,
but it grew with each morn,
no one heard its breath,
but it was there somehow born,
even without fuel,
and with water all around,
after suffering the duel,
it nevertheless went ahead,
and became very cruel,
though it seemed vague,
shut inside the cage,
it spread like the plague,
with a wild rage,
was it too late,
the heat was unbearable,
efforts to stop were in vain,
the nightmare was terrible,
it caused too much pain,
still no one noticed the trouble,
no one knew it burn,
no one knew its warmth,
it grew with each morn,
no one heard its breath,
yet the fire in me is still burning.