Where does “blei” come from?

blei (German) comes from Middle High German blī, from Old High German blīo, from Proto-West Germanic blīwī, from Proto-Germanic blīwiją, from Proto-Indo-European mliH-wó-s, from Proto-Indo-European mleh₁y- — to be weak, weary, tired.

blei (German): lead (chemical element - Pb, atomic number 82)