Weyoun 4
Weyoun 4 was a Vorta who was encountered by the Federation in 2372 as the supervisor of a Jem'Hadar attack ship and its crew of Jem'Hadar, led by Omet'iklan. 

After his ship was attacked by a group of renegade Jem'Hadar, Weyoun chose to recruit the assistance of Captain Benjamin Sisko in quelling the rebellion. Weyoun withheld crucial information from Omet'iklan about the rebels' fortress: an Iconian gateway on Vandros IV. However, the Jem'Hadar under Weyoun's supervision remained loyal to the Founders and successfully completed the mission of eradicating the Jem'Hadar rebellion. Following the battle, Omet'iklan killed Weyoun for questioning his loyalty to the Dominion. ()

Weyoun was later referenced by Kilana during her encounter with Sisko in 2373, where she recalled that "Weyoun's report on you was right. You are direct. I like that." ()

Later that year, when Sisko met Weyoun 5, he commented: "I saw you die". Weyoun explained that Sisko had met Weyoun 4. ()

Sisko later recounted his memories of Weyoun 4 and his death to Remata'Klan in 2374. Remata'Klan stated that such incidents only occurred in units that had lost discipline. ()

Appendices

Background information 
Weyoun 4 was portrayed by Jeffrey Combs, in his first of five Weyoun appearances.

According to the script for "To the Death", when Weyoun slaps Odo on the shoulder, he infected him with the virus that presents itself in  and necessitates his return to the Great Link.  This intent wasn't immediately clear in the episode itself.

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Vorta
Bioreplicants
Government officials