  We report observations and analysis of the nearby gamma-ray burst
GRB\,161219B (redshift $z=0.1475$) and the associated Type Ic supernova (SN)
2016jca. GRB\,161219B had an isotropic gamma-ray energy of $\sim 1.6 \times
10^{50}$\,erg. Its afterglow is likely refreshed at an epoch preceding the
first photometric points (0.6\,d), which slows down the decay rates. Combined
analysis of the SN light curve and multiwavelength observations of the
afterglow suggest that the GRB jet was broad during the afterglow phase (full
opening angle $\sim 42^\circ \pm 3^\circ$). Our spectral series shows broad
absorption lines typical of GRB supernovae (SNe), which testify to the presence
of material with velocities up to $\sim 0.25$c. The spectrum at 3.73\,d allows
for the very early identification of a SN associated with a GRB. Reproducing it
requires a large photospheric velocity ($35,000 \pm 7000$\,\kms). The kinetic
energy of the SN is estimated through models to be \KE $\approx 4 \times
10^{52}$\,erg in spherical symmetry. The ejected mass in the explosion was \Mej
$\approx 6.5 \pm 1.5$\,\Msun, much less than that of other GRB-SNe,
demonstrating diversity among these events. The total amount of \Nifs\ in the
explosion was $0.27 \pm 0.05$\,\Msun. The observed spectra require the presence
of freshly synthesised \Nifs\ at the highest velocities, at least 3 times more
than a standard GRB-SN. We also find evidence for a decreasing \Nifs\ abundance
as a function of decreasing velocity. This suggests that SN\,2016jca was a
highly aspherical explosion viewed close to on-axis, powered by a compact
remnant. Applying a typical correction for asymmetry, the energy of SN\,2016jca
was $\sim$ (1--3) $\times 10^{52}$\,erg, confirming that most of the energy
produced by GRB-SNe goes into the kinetic energy of the SN ejecta.
