The developers have created a new POS consent algorithm, called Ouroboros.
This algorithm is the first to be verified mathematically and to have proof of its effective functioning.
It is led by Professor Aggelos Kiayias, and is crucial to the functioning of the cardan ecosystem.
What they want to do on cardano is to create a more secure bitcoin blockchain using a consensus algorithm that consumes little energy but at the same time increases efficiency.
Unlike Bitcoin which uses the POW, the cardan cryptocurrency uses the POS which drastically reduces its energy consumption.
The block validation occurs through randomness, that is, in bitcoin you have the proof of strength where the strongest arrives first to validate the block and receive the reward.
Instead, in Cardano, the block validator is randomly assigned and receives the reward based on the frozen Cardan tokens divided by the total tokens in the network.
This process is a safer way to demonstrate the validity of validators, using randomness.
The stakeholder role is fundamental because it is he who maintains the entire network, it has the difference of a system with delegation (DPOS) like Eos.
This video explains the operation in detail.