Green’s Dictionary of Slang

hector n.

also bully-hector
[an ironic use of the Trojan hero Hector, son of Priam and Hecuba, husband of Andromache, ‘the prop or stay of Troy’; thus note Shadwell, The Squire of Alsatia (1688): ‘They are all of them as stout as Hector’]

[mid-17C–mid-19C] a blustering, swaggering bully, a thug, a bouncer, esp. of a brothel.

In phrases Hector [? euph. for SE hell]

[20C+] (US) used in a variety of phrs., e.g. dead as Hector, mad as Hector, meaner than Hector.