Harva was one of the thousands of EMH Mark 1’s issued across the Federation, and ultimately recalled when personality emerged to produce sapient AI. Their service was spotty at best, only activate for a handful of hours prior to the decommission. As they are sapient, they had to acknowledge rights and grant them right to travel. With nobody really having accommodations for a holographic crew member Harva spent much of their time in digital oblivion awaiting activation in a Federation database.
The most recent activation saw him assigned to a Klingon Stateship “VaqBach” on deep space assignment. Her time there was spent mostly in oblivion, but a series of escalating conflicts saw them get more usage. The death of the CMO saw an under-trained Anslo Tol as the new CMO, and Harva became a source of knowledge and skill desperately needed.
Harva carries a grudge to the Klingos who mistreated them and the animosity shows through. Having witnessed them in all their best and worst states, they will assist but has no desire to actually save lives of these “uncivil brutes.” Though she is told time and again that “true intelligence” yields empathy and compassion, observation proves otherwise.
Harva is an EMH mark 1 that was donated to Klingon ships as a form of getting rid of "defunct" Mk. 1 EMH. Harva is a tracked commodity nonetheless, and was assigned to the VaqBach for its long range mission. The Vaq Bach has a very large medical facility, and several off sites for emergency visits to far off corners, but Harva doesn't get out much. The Klingons on board largely treat him like a console without buttons and shout orders at them.