I stumbled on the solution.. Thought Im still confused why my $MANPATH is blank.
I've will posted for the the rest
makewhatis reads all the manual pages contained in the given sections of manpath or the preformatted pages contained in the given sections of catpath. For each page, it writes a line in the whatis database; each line consists of the name of the page and a short description, separated by a dash. The description is extracted using the content of the NAME section of the manual page.