A strong desire to leave a legacy comparable to that of Deng Xiaoping and a sense of crisis over the survival of the Communist Party are driving President Xi Jinping's relentless fight against corruption, say people connected to the party's inner circle.
The president will use the crusade against corruption to sweep away resistance to his ambitious reform agenda, as entrenched interest groups have become too powerful and are reluctant to change, they say.
Xi, who greatly admires Deng, wanted to become a leader in a similar vein, who could lead China into a new era of reform and growth, said sources including senior officials and "princelings" - the children of former high-ranking leaders.
They said Xi identified himself strongly as a member of the princeling group and saw it as his mandate and mission to revive the party, whose ruling bases have been eroded by rampant corruption and bureaucracy.
Watch: China's Xi cementing power with probe into Zhou: analyst
"Xi is inspired to claim his own place in history as one of the party greats. To achieve this, he needs to consolidate power and weaken the resistance to reforms," said a princeling who has known the president for decades.
"He [Xi] could take it easy by finishing his time in office without making any major change, just like his predecessor [President Hu Jintao ] did.
"But he chose a more difficult path because of his strong sense of responsibility as a son of the revolutionaries."
The president's father, Xi Zhongxun , who died in 2002, was a party elder who helped establish the People's Republic in 1949 and later led the vanguard of Deng's economic reforms in the late 1970s.
While both his predecessors launched anti-corruption campaigns in the early days of their presidencies, Xi's drive is unprecedented.
On Tuesday, China broke the decades-old political taboo of not prosecuting the highest-ranking officials for corruption by publicly announcing a probe into former security tsar Zhou Yongkang . Just a month ago, the leadership under Xi expelled a former vice-chairman of the Central Military Commission, Xu Caihou , from the party for corruption.
In his first 20 months in office, Xi's anti-corruption drive has claimed at least 36 officials of vice-ministerial or higher rank - seven more than his predecessor Hu Jintao managed in his first three years.
"This is a party purge, aimed at people and cliques that are seen as weakening the party's legitimacy and harming its image and stability," said Kerry Brown, professor of Chinese politics at the University of Sydney.
"It is not so much about material wealth as such, but more about imposing a new moral image and a new legitimacy on the party. That is much more fundamental."
Party insiders said Xi was determined to use the campaign to break down the pockets of resistance to his comprehensive reform plans.
But many critics also accused Xi of using it to thwart party rivals and install his own people in power.
"Xi Jinping clearly saw corruption as a serious threat to the party and the country, but he also saw anti-corruption as a good way to build his reputation," said Dali Yang, a professor of political science at the University of Chicago. "It certainly helped that he could install more people to his liking."
Xi has quietly installed many princelings and close allies into important posts since taking office. For instance, Chen Zhiya, a son of Communist general Chen Geng, was made the deputy minister of the People's Liberation Army's intelligence department last year on Xi's order, sources said.
"Xi trusts the princelings because he believes we share similar underlying ideas - we all treasure the party and the nation founded by our fathers and dislike officials who know no discipline or limits in their accumulation of wealth," said a princeling source.
To answer his critics, the president had asked disciplinary inspection teams to be sent to his old power bases, the source said. Both Shanghai and Zhejiang - where Xi once governed - are included in the latest round of inspections. This was to prove that Xi was ready to tackle anyone, friend or not, who violated the party rules.
A source said the president made a strongly worded speech in late June warning the party elite that nothing would be off limits in his anti-graft drive.
Steve Tsang, director of the China Policy Institute at the University of Nottingham in Britain, said Xi wanted to reform the party as well as increase his power.
"Xi clearly wants both, which is to use the anti-corruption campaign to install his own people and to strengthen the capacity of the party as a Leninist instrument of control. They are mutually reinforcing from Xi's point of view."
Still, the outcome of his anti-corruption drive is uncertain.
Jonathan Holslag, research fellow at the Brussels Institute of Contemporary China Studies, said there were risks.
"If the economic climate continues to deteriorate, he will be the one to attract the ire of his public. It also creates more resistance from within the system, especially when he goes after the protégés of other senior party members."
Brown said the success of the anti-graft drive would ride on the party itself. "They [the leadership] want the party to become more of a vanguard force as China continues to become a global power. If the party is weak, disorganised and chasing material profit all the time, this mission is jeopardised."
Watch: Former security chief Zhou Yongkang at an NPC meeting in 2012