יד וְהַקָּרֹב אֵלָיו כַּרְשְׁנָא שֵׁתָר אַדְמָתָא תַרְשִׁישׁ מֶרֶס מַרְסְנָא מְמוּכָן שִׁבְעַת שָׂרֵי פָּרַס וּמָדַי רֹאֵי פְּנֵי הַמֶּלֶךְ הַיּשְׁבִים רִאשֹׁנָה בַּמַּלְכוּת
14. And close to him were Karshena, Shesar, Admasa, Tarshish, Meres, Marsena, Memuchan – seven ministers of Persia and Medea – who see the face of the king, first to sit in royalty.
According to the Malbim, the king wanted, more than anything else, to keep this story private, so he chose a group of people “close to him,” who could keep it that way. Achashverosh felt impotent and week, and this was not the image of himself that he wanted projected to his people.