Gremmy Thoumeaux is a Quincy and member of the Vandenreich Sternritter, bearing the title of V: The Visionary, which symbolizes his gift — the ability to make imagination a reality. His appearance is deceptive: at first glance he looks like a child, yet his true form is a brain enclosed in a protective container. The body the world sees is merely a product of his own power.
Gremmy takes pride in his gift and sincerely believes that imagination is the greatest power in the entire universe. He is distinguished by extreme arrogance and self-confidence: he considers himself the strongest among the Sternritter and does not hide this. At the same time, Gremmy is cruel not only to his enemies, but also to the creations of his own imagination, and shows complete indifference toward his comrades-in-arms. His power was so dangerous that some Sternritter openly opposed his release.
A turning point in Gremmy's fate came in his battle with Zaraki Kenpachi. For the first time, he felt a burning desire to win at any cost. Gremmy threw into the fray the most varied creations of his fantasy: molten lava, water, firearms, rockets, his own clones, and even a meteorite. However, his boundless power played a cruel trick on him — his body could not withstand its own might and literally fell apart.
In the face of death, Gremmy admitted his defeat and for the first time experienced loneliness, reflecting on a world devoid of imagination. Thus perished one of the most dangerous and at the same time tragic Sternritter of the Vandenreich.