idk, this is what i read on the book in Oblivion called: On Morrowind
You didn't read that in
On Morrowind. The only statement that any combat between Imperial and Dunmer occurred at all is
"Contrived border incidents in Black Marsh ended inconclusively"
Redoran did not fight the Empire. They may have been ready to, but
"The situation changed radically when Vivec appeared in person in Vivec City to announce his negotiation of a treaty with Emperor Tiber Septim, reorganizing Morrowind as a province of the Empire, but guaranteeing 'all rights of faith and self-government.'"
There were, however, some scores settled between Hlaalu and Indoril:
The Lord High Councilor of the Grand Council, an Indoril, refused to accept the treaty, and refused to step down. He was assassinated, and replaced by a Hlaalu. House Hlaalu took the opportunity to settle some old scores with House Indoril, and a number of local councils changed hands in bloody coups. More blood was shed in these inter-house struggles than against the Imperial Legions during Morrowind's transition from an independent nation to a province of the Empire.