  We identify in Einstein gravity an asymptotic spin-$2$ charge aspect whose
conservation equation gives rise, after quantization, to the sub-subleading
soft theorem. Our treatment reveals that this spin-$2$ charge generates a
non-local spacetime symmetry represented at null infinity by pseudo-vector
fields. Moreover, we demonstrate that the non-linear nature of Einstein's
equations is reflected in the Ward identity through collinear corrections to
the sub-subleading soft theorem. Our analysis also provides a unified treatment
of the universal soft theorems as conservation equations for the spin-0,-1,-2
canonical generators, while highlighting the important role played by the dual
mass.
