  Recently, very massive compact stellar systems have been discovered in the
intracluster regions of galaxy clusters and in the nuclear regions of late-type
disk galaxies. It is unclear how these compact stellar systems -- known as
``ultra-compact dwarf'' (UCD) galaxies or ``nuclear clusters'' (NCs) -- form
and evolve. By adopting a formation scenario where these stellar systems are
the product of multiple merging of star clusters in the central regions of
galaxies, we investigate, numerically, their physical properties. We find that
physical correlations between velocity dispersion, luminosity, effective
radius, and average surface brightness in the stellar merger remnants are quite
different from those observed in globular clusters. We also find that the
remnants have triaxial shapes with or without figure rotation, and these shapes
and their kinematics depend strongly on the initial number and distribution of
the progenitor clusters. These specific predictions can be compared with the
corresponding results of ongoing and future observations of UCDs and NCs,
thereby providing a better understanding of the origin of these enigmatic
objects.
