  A spinning supermassive black hole (SMBH) at the core of an active galactic
nucleus (AGN) provides room for the elusive ultra-light scalar particles (ULSP)
to be produced through a phenomenon called \textit{superradiance}. As a result
of this phenomenon, a cloud of scalar particles forms around the black hole by
draining the spin angular momentum of the SMBH. In this work, we present a
study of the superradiant instability due to a scalar field in the vicinity of
the central SMBH in an AGN. We begin by showing that the time-evolution of the
gravitational coupling $\alpha$ in a realistic ambiance created by the
accretion disk around the SMBH in AGN leads to interesting consequences such as
the amplified growth of the scalar cloud, enhancement of the gravitational wave
emission rate, and appearance of higher modes of superradiance within the age
of the Universe ($\sim 10^{10}$ years). We then explore the consequence of
superradiance on the characteristics of the AGN. Using the Novikov-Thorne model
for an accretion disk, we divide the full spectrum into three distinct
wavelength bands- X-ray ($10^{-4}-10^{-2}~\mu$m), UV (0.010-0.4~$\mu$m), and
Vis-IR (0.4~$\mu$m-100~$\mu$m) and observe sudden drops in the time-variations
of the luminosities across these bands and Eddington ratio ($f_{\textrm{Edd}}$)
with a characteristic timescale of superradiance. Using a uniform distribution
of spin and mass of the SMBHs in AGNs, we demonstrate the appearance of
depleted regions and accumulations along the boundaries of these regions in the
planes of different band-luminosities and $f_{\textrm{Edd}}$. Finally, we
discuss some possible signatures of superradiance that can be drawn from the
observed time-variation of the AGN luminosities.
