sympathetic

The timing of the invasion would seem to have arisen from awarness that the ruling Ethiopian dynasty was not popular; fragmented politics and divided loyalties wtihin the country seemed to offer the Assyrians an opportunity to use their military power to displace Taharqa and impose a native regime sympatethic to themselves.

Hello. Please help me with this word here. Does it mean proper or friendly, kindly disposed? Thanks a lot.

Yes, kindly disposed ... with a touch of collaborating, most likely. An imposed native regime might be referred to as a puppet regime, i.e. it does what the imposing power tells it to do.

It could mean having more common interests with the Assyrians.

Thanks a lot