Simplify the following text for a Grade 10 native English-speaking person.
Original: Karel Willem Frederik Marie Doorman ( April 23 , 1889 - February 28 , 1942 ) was a Dutch Rear admiral who commanded ABDACOM , a hastily-organized multinational naval force formed to defend the East Indies against an overwhelming Imperial Japanese attack .
Simplified: Karel Willem Frederik Marie Doorman ( April 23 1889 - February 28 1942 ) was a Dutch admiral ( Dutch : schout-bij-nacht ) during World War II .