Gustav Heydrich is a character from the #COMPASS2.0 ANIMATION PROJECT who serves as the commander of a brutal military force. He is clad in poisonous weaponry and is allied with Tadaomi Oka, with the two of them plotting to unify the world together. In terms of his physical appearance, Gustav is a man of muscular build with blonde hair parted on the right and purple eyes. His right eye bears a purple-colored scar from a single slash, and the lower half of his face is always covered by a black gas mask decorated with faux fangs. This gas mask connects to headphone-like earmuffs and two pipes that lead to a complex poison tank he wears on his back. His attire consists of a red, skintight bodysuit under a black jacket with red and silver linings, camouflage-patterned chaps, and black boots with steel plates protecting his knees. Across his left thigh, a strap holds seven tubes of a purple-colored liquid, and the palms of his hands have circular metal vents that can release gas at will. The poison tank itself is an intricate apparatus featuring multiple pairs of exhale pipes and valves.

Gustav's personality is defined by an obsession with the concept of despair, which he pursues to a nearly extreme degree. He is extremely cruel toward nearly everyone he encounters, yet he is also surprisingly intelligent and well-informed on subjects like strategy, medicine, and biology. His past is marked by significant trauma; as a very young boy, he was experimented on to become an ultimate weapon of war, which is likely the reason for his current physical state, including a very weak respiratory system that causes him ongoing pain. This traumatic experience in his childhood robbed him of his youth, and although he has grown into a cruel adult, he still retains some aspects of his younger self and harbors a complex about his age and maturity. Despite having been deeply traumatized himself, he continues the cycle of abuse by inflicting experiments on others against their will. Gustav is more than willing to sacrifice his life for power, and beyond that, he is willing to sacrifice himself simply for the sake of dying, often attempting to convince others to administer higher and higher dosages of lethal medicine to himself.

Regarding his motivations and role in the story, Gustav is driven by a desire to spread despair and destroy the world, showing little interest in grander ideals. He demonstrates great loyalty and devotion to his military ally Tadaomi Oka, though he openly admits that he does not care about Tadaomi's grandiose objectives and simply wants to destroy the world alongside him. The two are frequently depicted as a pair, appearing together in various scenes including working out, cheering for one another in battle, and attending festivals. However, there is a notable imbalance in their dynamic, as Tadaomi does not talk about Gustav nearly as much as Gustav talks about Tadaomi.

In terms of his abilities, Gustav possesses a unique and dangerous combat style centered around poison. His hero ability, Restricted Compensation, causes him to constantly lose health over time, meaning that without regular healing, he will die from his own life-draining effect. His hero action, Wave of Contraindication, allows him to recover his own life while simultaneously inflicting poison damage on all enemies within his immediate area. This ability deals percentage-based damage, making it particularly effective against highly durable opponents. His hero skill, Grausam Schmelz, poisons all enemies in the arena, and after several seconds, their health is reduced to a fraction of its maximum, ignoring guard abilities. Gustav is noted for having the highest possible multipliers for both defense and health combined with fast movement speed for a character of his tank role, making him specialized for offense despite his defensive nature. However, his constant health drain is a necessary drawback that compensates for these exceptional stats.