Softly spoken and easily embarrassed, Teng Biao has a reserved, childlike gentleness. Yet few people have his moral courage to speak up for what they believe in, particularly when there is a price to pay.
On the 25th anniversary of the Tiananmen crackdown on June 4, the mainland law academic made an impassioned speech at the candlelight vigil in Hong Kong's Victoria Park, criticising the persecution of political activists on the mainland.
"The massacre did not stop in 1989. The killing, in the name of a political 'campaign', in the name of law, in the name of maintaining stability, in the name of state unity, has never stopped," Teng told the crowd.
For the past two years, Teng has been a visiting scholar at Hong Kong's Chinese University. He leaves in a few days to take up a visiting position at Harvard University in the United States.
But Hong Kong, the mainland and universal rights are unlikely to be far from his thoughts.
In his speech to the crowd in Victoria Park, Teng proclaimed his support for the push in Hong Kong for universal suffrage and the Occupy Central movement, saying he "also looks forward to occupying Tiananmen Square with love and peace one day".
Teng knew his declaration would antagonise the authorities. He said they had warned him to stay away from the vigil or face "serious" consequences - something that he believed would probably include arrest if he returned to the mainland.
Over the past year and a half, scores of his friends and fellow campaigners, including legal scholar Xu Zhiyong and lawyer Ding Jiaxi of the New Citizens Movement, have been jailed over their calls for officials to declare their assets.
Without going into specifics, he said mainland authorities were now targeting his family as a way of punishing him. But he insisted: "I cannot give in."
And the 41-year-old legal scholar has no regrets about what he said in Victoria Park.
Teng, who started his human-rights career a decade ago, has paid a heavy price for his work. A law lecturer at the China University of Politics and Law in Beijing, he was suspended from teaching three times and stripped of his lawyer's licence in 2008 because of his activism.
Before the Beijing Olympics, he was hooded, forcibly taken away by secret police and held for days after speaking out against the country's rights abuses.
In 2011, he was arbitrarily detained in solitary confinement for 70 days.
Teng said that even though detention filled him with a sense of fear and isolation, it did not diminish his determination to pursue rights for his fellow citizens.
"It's a terrible feeling … you're mentally broken and you think anything could happen. But I cannot give up … the call of my conscience," the father of two young children said. "For the next generation, I have to fight for a society that is free from fear."
Teng stumbled into the human-rights cause. In 2003, soon after he graduated from Peking University with a doctorate in law, he and fellow students Xu and Yu Jiang were outraged by the death of a young graphic designer in police custody in Guangzhou. They petitioned for a review of the regulation that gave police the power to arbitrarily detain people found without urban residency permits in cities.
Much to their surprise, the government scrapped the regulation the following month. Teng said he was "filled with hope" and decided to devote his life to human-rights work.
He and his two friends soon founded a non-profit legal aid centre, the Open Constitution Initiative, which sought rights for the underprivileged such as petitioners held in illegal "black jails", death-row inmates and migrants' children without schooling. But the centre's work touched a nerve with the authorities and it was forcibly closed in 2009 over alleged tax evasion. Teng said it was ironic how he and Xu, lauded in 2003 by state media for their contributions to the rule of law, ended up considered "enemies of the state".
"But we haven't changed, we're still pushing the rule of law and human rights - it's the government that has changed; they now see us as troublemakers."
Over the years, he has also defended persecuted Christians and members of the banned Falun Gong sect, founded his NGO China Against the Death Penalty and co-founded the New Citizens Movement.
But more than a decade after Teng started his mission of defending human rights, the situation seems bleaker than ever. Since March last year, around 300 rights activists had been detained or arrested, he said.
Teng sees the intensified crackdown on lawyers, journalists, liberal scholars, churches and religious cults as part of the central government's "ideological purification campaign" and instinctive reaction to deal with a more robust civil society.
He said the government had changed the way it handled grass-roots opposition from the previous strategy of "stability maintenance" to one of "eradication" since President Xi Jinping took power in late 2012.
Since last year, the authorities have stressed the importance of an ideological struggle against the dangers of "Western constitutional democracy", as well as "universal values" such as human rights, rule of law and democracy. "This is their mindset - one-party rule cannot be changed. If there is anything that can threaten that, then it must be repressed hard," Teng said.
But even though citizens' demands were often suppressed and rights campaign leaders often jailed, Teng said their work was still meaningful as it would raise public awareness of the rule of law and rights.
Repression "will have an intimidation effect … but the growth of civil society will continue," Teng said. "The hope is in civil society."