In the Unbound Universe, Skaro was the home planet of that universe's Kaleds, later Daleks, and Thals.
The underlying tensions between Skaro's two sentient races were aggravated by an attack from an alien race known as the Quatch who sought a vast well of dimensional energy that existed in Skaro's core. The attack led to the crippling of the Kaled scientist Davros and war between the Kaled and Thals. At the war's end, Davros turned his people into the Daleks. Davros' first batch of Daleks rejected him and subsequently left Skaro to conquer other planets. His second attempt wielded a faction of Daleks who, while devoted to conquest and order, were capable of pity and saw no need for genocide. Davros remained among these Daleks for a while but eventually abandoned them out of disappointment, venturing into space. Later generations of Daleks believed that he would day return.
At some point, when the Daleks threatened to destroy the Thals, the Doctor visited Skaro and thwarted them in what became known as the "Great Siege". The Daleks survived this defeat however and reclaimed their planet, enforcing a police state to prepare for the return of the Quatch.
When the Doctor returned, accompanied by Alistair Gordon Lethbridge-Stewart, he joined with the Thals to overthrow the Daleks' regime. Capturing one of the Daleks, the Doctor made it believe it was Davros, causing a civil war between those Daleks who believed it and those loyal to the Black Dalek before the Quatch, now allied with Davros, arrived.
After a captured Dalek had explained to the Doctor its race's benevolent intentions, the Doctor convinced the Daleks to ally with the Thals to defend Skaro with further discussion allowing the Daleks and Thals to deduce the Quatch's role in crippling Davros.
With Alistair's unconventional human military strategies allowing the Daleks to gain the advantage over the Quatch, the Doctor managed to enter the enemy flagship and informed Davros that the Quatch had crippled him. Turning on his allies, Davros destroyed the Quatch and saved Skaro. Though the Doctor was ready to leave in the aftermath, Alistair saw that tensions still existed between the Thals and Daleks, electing to stay on Skaro and try and mediate a permanent peace. (AUDIO: Masters of War)