Vegant is the main antagonistic force from Aleste 2.
The Vegant is a sentient humanoid race which evolved from plants. Due to their different form of metabolism, they were unable to consume food and digest it, so they had to absorb the life energy of animals to sustain themselves. Since this would quickly lead to the extinction of life on a planet, they have planted seeds on many young planets which would eventually generate new life, which they then waited to evolve into human life and for their civilization to peak, after which the planted seed would grow into a giant plant and take over the planet, sending a signal for the Vegant signifying the planet was ready to be harvested.
One of those seeds was planted on Earth, which eventually grew into a plant and took over the DIA51 supercomputer, who then sent a signal for the Vegant. The Vegant, under Emperor Gaizel's command, move their gigantic battleship towards Earth, intercepting the Earth's Shinano military cruiser which was under Ray Waizen's command and destroying it, after which they begin their attack on Earth.
In order to fight the Vegant's forces, Earth's military sends in Ellinor Waizen, Ray's daughter, to pilot the new generation Aleste fighter. During her mission, she attacks a Vegant base on the sea, only to be taken to another dimension by Brahwell, who commanded the Vegant aerial fleet. Upon destroying Vallantus, Brahwell's battleship, he comes out of the wreckage and reveals three months have passed in the real world.
As Ellinor returns to the real world, she finds that the Vegant have almost taken over the entire world with the sea covered by plants and cities destroyed by mutants, so she decides to attack their mothership directly. She confronts Gaizel directly inside the mothership and defeats him, thus defeating all the Vegant forces for good.