deriv LSK ETT STT aSTA ALPH OLDHOMEPAGE NEWHOMEPAGE
padafinal z श् is never allowed in real Sanskrit, some rule or other always changes it into D ड् or into k क्, as in IT ईट् "lord" or **dik दिक् "quarter of the sky".
But a creator is allowed to break his / her / its own rules, so words made up by /pANini are allowed to keep their odd padafinal consonants like l ल् c च् z श् Th ठ् in a sUtra whenever /pANini feels like it.
The rules vRddhirAdaic, etyedhatyUThs..., etadoz are examples.