  We report the discovery of a radio relic in the northeastern periphery of the
cluster Abell 2108 (A2108). A2108 is a part of the uGMRT LOw-MAss Galaxy
Cluster Survey (GLOMACS), where our main aim is to search for diffuse radio
emission signatures in very sparsely explored low-mass galaxy clusters using
uGMRT band-3 (central frequency 400 MHz). We used our uGMRT band-3 data along
with the existing archival band-3 uGMRT data to improve image sensitivity.
Along with the previously reported southwestern relic, the discovery of the new
relic makes A2108 one of the few low-mass clusters hosting double relics. The
new relic spans over a region of 610 kpc $\times$ 310 kpc and, interestingly,
differs considerably in size and morphology from the other relic. With
XMM-Newton science archive data, we also report the tentative detection of a
mildly supersonic shock of Mach number $\mathcal{M}_\mathrm{SB}=1.42$ and
$\mathcal{M}_\mathrm{T} = 1.43$ from the surface brightness and temperature
discontinuities, respectively near this newly found relic. Both the relics in
A2108 are found to be significantly under-luminous compared to other double
relic systems in the mass-luminosity plane. Though mild supersonic shocks
resulting from an off-axis merger could have influenced their origin, we
hypothesize that further local environments have played a crucial role in
shaping their morphology.

High Energy Astrophysical Phenomena;Cosmology and Nongalactic Astrophysics;Astrophysics of Galaxies