  In the unknown territory of transfermium nuclei, the relativistic mean-field
(RMF) theory has been applied to probe decay modes which include
$\alpha$-decay, spontaneous fission (SF), and a less explored weak-decay. These
decay modes are analyzed on equal footing for 101$\leq$Z$\leq$109 and as a
consequence, the half-lives for weak-decay are indeed found comparable for
several isotopes. Our prediction of decay modes and half-lives are found in
excellent agreement with available experimental decay modes and half-lives
along with the results of some other theories. Out of $\alpha$, $\beta^+$/EC,
$\beta^-$, and SF, the most probable decay mode is anticipated along with its
half-life over a wide range of odd and even nuclei to frame a novel sight into
terra incognita.
