  The issue concerning rigorous methods recently developed in deriving the
asymptotics of quasi-normal modes is revisited and applied to a generic non
rotating multi-horizon black holes solution. Some examples are illustrated and
the single horizon cases are also considered. As a result, the asymptotics for
large angular momentum parameter is shown to depend on the difference between
the maximal or Nariai black hole mass and the ordinary black hole mass. The
extremal limit is also discussed and the exact evaluation of the quasi-normal
frequencies related to the Nariai space-time is presented, as a consistent
check of the general asymptotic formula.
