Jango the Ripper is a notorious criminal and one of the most wanted men in Aleroth. He can be found at the Wild Willows Manor, an asylum in the Crow's Nest district during the events of Divinity II: Flames of Vengeance.
Jango appears, seemingly out of nowhere, while you are walking back towards the reception / waiting room area after you've attempted to activate the pressure plates in the eastern wing of the building, and have explored the southeastern area of the asylum. You automatically enter a discussion and he says that the only way out of the asylum is in a coffin. If you choose the dialog option about an oak casket, battle ensues immediately.
If you choose the option concerning polite conversation, he is taken by surprise and you can suggest activating the pressure plates. Despite his bloodthirsty reputation, his greed is stronger than his lust for violence. In hope of finding hidden treasure, he agrees to work together. When you step on one of the pressure plates, he steps on the other, raising the wall to allow access to the northeastern area of the asylum. Jango is disappointed with what you find there.
Approaching the asylum's entrance causes him to engage you in conversation again. You can choose to fight him, or allow him to leave. If you let him go, he unexpectedly shows sympathy towards the incarcerated patients by giving you the Cage Key, allowing you to free Teddy. He leaves, and you fail the quest A Hunting We Shall Go Once More.
If you choose to fight Jango (level 40) at any time, he drops random loot, the Cage Key needed to free Teddy, as well as Jango's Bracelet (a quest item you can bring to Balbus at the Circle of Trust Inn for A Hunting We Shall Go Once More) when killed. If freed, Teddy can be asked to step on the pressure plates in place of Jango.