Daring to take on the taboo topic of the monarchy is also a first.
Under the constitution, the royals — including super-rich King Maha Vajiralongkorn — are supposed to stay out of politics, but they wield enormous clout.
Since the king took the throne in 2016, he has made unprecedented changes, taking direct control of the palace's fortune and moving two army units under his command.
At his side are the arch-royalist military and powerful billionaire clans.
What's the reaction?
Mixed. The student-led protests in Thailand have drawn support from a broad demographic, including many from the working class.
The movement has also spread to high schools across the country, with teenagers tying white bows of solidarity in their hair and on backpacks.
But pro-royalist groups have held their own, smaller counter-demonstrations with mostly older protesters enraged at the perceived affront to the monarchy.