Glossary
What is a Bateratze in 1666: Amsterdam? (The Union, Explained)
In 1666: Amsterdam, a Bateratze is the Union of a Zaindaris witch — a bonded companion bound through the commencement ritual. In the game's English localisation the same bond is called the Union.
Updated Aug 28, 2026
The definition
The game introduces the term in its own dialogue: when Aaron's cat arrives in the forest where Noa is waiting, she greets him with "Welcome, Bateratze. Welcome, Aaron." English coverage renders the relationship as "her Union" — sirusgaming describes the cat as "her Bateratze, her Union, with the cat formerly known as Aaron Long-Smith."
Linguistic note (not official): bateratze is a Basque word meaning "unification" or "union," which matches how the English localisation uses "Union." The developers have not published an official glossary.
Who is Aaron?
Aaron is a man from 1999. On December 30, 1999, he was in Amsterdam with his girlfriend Agnes for the millennium celebrations. Agnes prepared a ritual in their hotel room with ancient relics and mirrors placed around the bed; by the end of it Aaron had become a cat, found himself in a frozen forest, and was claimed by Noa as her Union. He is also Clio's father, and the Prologue is framed as Clio reading the letter he left her.
What the Bateratze does in gameplay
- Scouting and mobility: jumps to high places, squeezes through small gaps, scales buildings
- Infiltration: scratches people who fear cats, then possesses and controls them to walk past guards
- Interaction: unlocks doors from the far side, opens windows for Noa, meows to attract guards
- Switching between Noa and Aaron is quick, and missions are built around the two working together
The cat appearance choice
During Noa's commencement ritual you choose one of nine named cats (Spirit, Hermit, Dreamer, Wildling, Guardian, Alchemist, Child, Page, Knight). The choice changes the cat's look and name only — the cat is always Aaron, as confirmed in-game. Whether the choice will affect anything in the full game is unconfirmed.
Zaindaris context
The Zaindaris are the tribe of witches Noa belongs to. They give power to beings called the Originals; when the contract ends, it is The Collector's job to take the power back. The Bateratze is part of this system: a companion the witch can rely on during the hunt.
Bateratze questions
What does Bateratze mean in 1666: Amsterdam?
Bateratze is the Zaindaris term for a witch's Union — a bonded companion. Noa's Bateratze is Aaron, a man from 1999 who becomes her cat companion.
Is Aaron a Bateratze?
Yes. Noa greets him in-game with 'Welcome, Bateratze. Welcome, Aaron.' The English localisation also calls the bond a 'Union'.
Does the cat choice matter in 1666: Amsterdam?
In the Prologue and the current EA content, the choice of nine cats changes appearance and name only — the cat is always Aaron. Whether it affects the full game is unconfirmed.
How do you get a Bateratze?
A Bateratze is bound through the Zaindaris commencement ritual, which Noa performs at the start of the Prologue.
Sources: Steam store page, Sirus Gaming — Prologue impressions. 1666: Amsterdam content and assets remain the property of Panache Digital Games.