Mahathir, who served Malaysia for more than two decades in two stints as prime minister, is leading one of several opposition coalitions looking to unseat the graft-tainted Barisan Nasional - led by incumbent premier Ismail Sabri Yaakob - in an election on Nov. 19.
In the previous polls in 2018, Mahathir came out of retirement and joined forces with Anwar to oust the Barisan government as it faced corruption allegations over the multibillion-dollar 1MDB scandal.
Mahathir promised to hand over the reins to Anwar but their multi-ethnic coalition collapsed in just 22 months due to infighting, paving the way for Barisan, led by Malay nationalist party UMNO, to return to power as part of another alliance.
Analysts say the votes of the country's majority ethnic Malays are expected to be split in the coming election between various Malay-centric parties that have emerged amidst the turmoil, including Mahathir's.
In what he said would likely be his final election foray, Mahathir vowed to fight "against bad Malays, criminal Malays… against the Malays who had destroyed this country."
Several UMNO leaders are facing graft charges brought against them by Mahathir's administration, including former Prime Minister Najib Razak, who was jailed for 12 years after being found guilty in September in a case linked to 1MDB. Najib denied wrongdoing.
Race and religion are divisive issues in multi-racial Malaysia, where ethnic Chinese and Indian minorities form a third of the electorate.
Opinion polls suggest the election will be tightly contested with no single party or bloc likely able to win a simple majority.
Mahathir said he would not work with UMNO, citing corruption allegations against the party he once dominated.
But he did not dismiss the possibility of working with Anwar's alliance, although he said the parties would need to have a discussion on who would be premier after the election.
"We don't agree that any one person should, even before the results come in, claim that he is the candidate for prime minister," Mahathir said.
Anwar in an interview with Reuters last week ruled out working with Mahathir and other coalitions, citing "fundamental differences."
The pair's rivalry has dominated Malaysian politics for decades, after Mahathir as premier sacked and jailed his then-deputy Anwar in 1998, accusing him of sodomy and corruption.
Anwar was released in 2004, rising to become opposition leader, but was re-imprisoned in 2015 on another sodomy charge, and has consistently said that all the accusations against him were politically motivated. He was pardoned in 2018 after the election win that removed UMNO from power for the first time in Malaysia's post-colonial history.
LAST ELECTION?
In what is likely to be his final election, Mahathir does not see his age as a hindrance in winning the support of first-time voters - the youngest of whom, at 18, are nearly eight decades his junior.
“I feel that the youth of today are much more mature than the youth of the past... I think they will look not just at age, but also at capability," Mahathir said.
Mahathir's alliance is not a major player and is not expected to win a significant number of seats.
Nevertheless, he was "reasonably confident" that his alliance could still come out tops, and purge the government of corruption, implement business-friendly policies, and restore the nation's standing as an ‘Asian Tiger’ economy.
The nonagenarian said he had no desire to be prime minister but would do so if asked to serve again.
Mahathir, who is running against four other candidates in his island constituency, Langkawi, said he would retire if he lost.
"I don’t see myself being active in politics until I’m 100 years old," he said. "The most important thing is to transfer my experience to the younger leaders of the party."
