  On February 12, 2021 two subsequent eruptions occurred above the West limb,
as seen along the Sun-Earth line. The first event was a typical slow Coronal
Mass Ejection (CME), followed $\sim 7$ hours later by a smaller and collimated
prominence eruption, originating Southward with respect to the CME, followed by
a plasma blob. These events were observed not only by SOHO and STEREO-A
missions, but also by the suite of remote sensing instruments on-board Solar
Orbiter (SolO). This work shows how data acquired by the Full Sun Imager (FSI),
Metis coronagraph, and Heliospheric Imager (SoloHI) from the SolO perspective
can be combined to study the eruptions and the different source regions.
Moreover, we show how Metis data can be analyzed to provide new information
about solar eruptions.
  Different 3D reconstruction methods were applied to the data acquired by
different spacecraft including remote sensing instruments on-board SolO. Images
acquired by both Metis channels in the Visible Light (VL) and H I
Lyman$-\alpha$ line (UV) were combined to derive physical information on the
expanding plasma. The polarization ratio technique was also applied for the
first time to the Metis images acquired in the VL channel. The two eruptions
were followed in 3D from their source region to their expansion in the
intermediate corona. Thanks to the combination of VL and UV Metis data, the
formation of a post-CME Current Sheet (CS) was followed for the first time in
the intermediate corona. The plasma temperature gradient across a post-CME blob
propagating along the CS was also measured for the first time. Application of
the polarization ratio technique to Metis data shows that, thanks to the
combination of four different polarization measurements, the errors are reduced
by $\sim 5-7$\%, thus better constraining the 3D distribution of plasma.
