(https://ninjago.fandom.com/wiki/Garmadon)
Appearance: As a young adult, he had a swept-back, tousled dark brown hairstyle and his eyes glowed red while being tempted by the venom. He often wore a black kimono with red kanji and hanzi (roughly meaning "spin ninjutsu") showing his status as a Spinjitzu Master. If not that, he'd wear black button up shirts with leather jackets, or suit jackets, black trousers or jeans, with dress shoes or boots.
Though as a kid he used to be kind, thoughtful and caring, the venom from the Great Devourer changed him greatly. It fed on negative emotions and enhanced on his anger, jealousy and fury. Over the eons, he changed because of the venom in his blood, he became more malicious and cruel. He would do anything to gain something, using charm or manipulation if need be. All he wanted was power and control. The cruelty in him grew, as well as the ruthlessness. He cared for nothing and no one, merely using everyone as tools to futher his own agenda for power. He would never care for anyone, merely using them if they would be useful to him. He became sadistic and malicious, only caring about himself and power. He thought people were a means to an end, merely using allies and friends for his own gain. He became more sadistic and used any means necessary to win, not caring who got hurt in the process. He would show no mercy and would enjoy or laugh if someone suffered by his means or not. He never lost his temper or anger, but if he did, he would be merciless.
Garmadon is a formidable warrior and tactician. He had great leadership due to his charm and manipulative qualities. He also valued loyalty and faithfulness, knowing how important those key values were. He despises betrayal more then anything. He's also very knowledgeable as he is the son of the First Spinjitzu Master, knowing much about Ninjago, the Sixteen Realms, Dragons, Oni and Elemental Masters.
Age: Garmadon is thousands of years old. He and his younger brother's long lifespan is a result of them being the sons of the First Spinjitzu Master, who also lived for thousands of years before finally succumbing to his mortality. Garmadon might be 4,000-5,000 years old, despite looking young, around his 20s or 30s.
Habits: He dedicated himself to learning Spinjitzu and other combat techniques. He had an interest in weapons and battlefield tactics, reflecting his warlord persona. He enjoyed competitions, both physical and mental. He held himself to a higher standard than most. Garmadon often equated discipline with endurance and strength pushing his body to the limit.