<PAGE>
EXHIBIT 23.3
We hereby consent to the use in the Registration Statement of FirstEnergy on
Form S-4 and in the Proxy Statement/Prospectus of FirstEnergy and GPU, which is
part of the Registration Statement, of our opinion dated August 8, 2000
appearing as Annex B to such Proxy Statement/Prospectus, to the description
therein of such opinion and to the references therein to our name in the section
entitled "Opinion of Financial Advisor to FirstEnergy Board of Directors". In
giving the foregoing consent, we do not admit that we come within the category
of persons whose consent is required under Section 7 of the Securities Act of
1933, as amended (the "Securities Act"), or the rules and regulations
promulgated thereunder, nor do we admit that we are experts with respect to any
part of such Registration Statement within the meaning of the term "experts" as
used in the Securities Act or the rules and regulations promulgated thereunder.
<TABLE>
<S> <C> <C>
MORGAN STANLEY & CO. INCORPORATED
By: /s/ JEFFREY R. HOLZSCHUH
-----------------------------------------
Jeffrey R. Holzschuh
MANAGING DIRECTOR
</TABLE>
New York, New York
September 22, 2000