President Xi Jinping may have tamed the "North-east Tiger" by toppling retired general Xu Caihou, but dealing with former military leader Guo Boxiong - the "North-west Wolf" - could be tricky politically, analysts say.
A wrong move could rock already shaky military unity and also have implications for Mr Xi's political authority, they add.
General Guo, who was sacked from the Chinese Communist Party on Thursday, is deemed to have more sway in the People's Liberation Army (PLA) than Xu, who died at the age of 71 in March while waiting to stand trial. Both were accused of handing out promotions in return for bribes and other benefits.
Gen Guo and Xu - whose nicknames were based on their respective powerbases in China's north-west and north-east regions - entered the powerful Central Military Commission (CMC) in 1999.
Though then-president Hu Jintao was the CMC chair from 2004, the Guo-Xu duo were effectively in charge of the PLA till their retirement in 2012.
Gen Guo, aged 73 this year, served longer as CMC vice-chair, from 2002, compared to Xu, whose stint began in 2004.
He also held command mostly over combat units in his 51-year military career, unlike Xu who was a political officer and was investigated in March last year in a pay-for-rank scandal.
Singapore-based observer Huang Jing said many in the military had worked closely with Gen Guo, and some may resort to desperate measures to protect themselves after his expulsion.
"The challenge for Mr Xi is to convince these people that they are safe, while still taking actions against those who need to be disciplined," he added.
Professor Huang of the Lee Kuan Yew School of Public Policy added that Gen Guo's enemies might seek revenge against his supporters.
Such a scenario could hurt unity in the PLA, where morale has been sapped by Mr Xi's anti-corruption campaign that has netted nearly 40 top brass since last year.
Yesterday, Heilongjiang military region's deputy commander Zhang Daixin was sentenced to 10 years' jail for corruption.
Analysts say Mr Xi will also have to deal with public concerns about the depth of military corruption, following the downfall of two former CMC vice-chairmen.
"It sends a message that the PLA has not been a competent fighting force but an army of corrupt officials," said Professor Bo Zhiyue, of the Victoria University of Wellington in New Zealand.
Observers say Mr Xi's latest move triggers questions about former president Jiang Zemin, who is seen as the patron of Gen Guo and Xu, and whether Mr Xi could set a precedent by targeting a former CCP chief.
"Based on the CCP's principle that the party controls the gun, the previous party leadership should then be responsible that two CMC vice-chair were found to have violated discipline for a long time," said Prof Huang.
"There may be pressure on Mr Xi to go after the one who had promoted and protected Guo.
That would require great political skills as well as resolve, given the risk of damaging the party's institutional image."
Beijing-based analyst Wang Xiangsui, of the Beijing University of Aeronautics and Astronautics, says structural reforms should be beefed up to stem military corruption. "The fall of two high-ranking leaders means we cannot blame it solely on their character flaws."