The Argonians didn't wait for the empire to save their hides, no. the Hist trees told the Argonians to charge into the gates at such a rate that the lieutenants of mehruns Dagon had to close the bloody gates!
Between Oblivion and Skyrim, the Argonians collectively took many levels in badarse. Counter invading HELL does make conquering what was left of Morrowind look a little weak, but it's still a gold star on their ledger Actually, the Argonians conquered more than the Thalmor on reflection.
Yup! The Argonians are fierce fighters, Tiber Septim needed a Giant golem based off of dwemer design to take down the Aldmari dominion (the Second?) while the argonians kept the Dominion at bay for years, striking in Elsweyr and even in the Valenwood. during their reign. I think they succeeded from the empire in the second Era. either way Argonians are tough as nails. but their problem was they don't have ambition the lands they took they didn't keep. sadly, but defeating the invasion of Tamriel by Dagon while everyone is Cyrodill shit themselves silly. thats a milestone.