Charm decays and $\tau$ physics at Belle and Belle II

Beyond $B$ physics, charm and $\tau$ physics constitute a central part of the Belle and Belle II physics programs. Here, we present recent results on charm baryon decays, including first measurements and observations of several previously unmeasured modes, together with new studies in $\tau$ physics. Particular emphasis is placed on searches for CP violation in $\tau$ decays and lepton-flavor-violating processes. In this context, a search for CP violation in $\tau \to \pi K_S{\nu }_{\tau }$ decays is reported for the first time.