Brand archetype
A brand archetype is a stock character borrowed from narrative theory, such as the Sage, the Rebel or the Carer, used as shorthand for how a brand should behave. It compresses personality into one recognisable pattern so a group can align quickly, at the cost of everything specific to that particular brand.
Brand archetype is not Brand positioning.
An archetype describes a manner: how you come across. Positioning describes a claim: who you are for, what you do better, and against which alternative. Two brands can share the Sage archetype and compete head on, because the archetype was never the thing separating them in the first place.
In practice
Archetypes reached marketing from Jungian psychology by way of mid-century advertising, and the twelve-character version is the one most people meet. Their appeal is genuine. They solve the problem where five people in a room all say friendly and mean five different things. Saying we are the Sage, not the Jester settles an argument in one sentence, using a vocabulary everybody already owns from stories they have read since childhood. As a compression device for personality, it works.
The limits are just as real, and worth stating plainly, because the framework is routinely oversold. An archetype describes manner with the content removed. It tells you how to come across and nothing about what you say, who you are for, or why anybody should pick you. It is also low resolution by design: there are twelve of them and considerably more than twelve brands, so whichever you choose is shared with thousands of others, several of them in your market. Adopting an archetype has never differentiated anyone.
The failure mode is substitution. A team runs an archetype workshop, lands on Explorer, enjoys the pleasant sensation of having decided something, and treats the positioning work as complete. What they have is a mood, and moods produce generic work. The tell is easy to check: if the resulting copy could be lifted onto a competitor's site with only the product name swapped, the only thing that was ever specified was temperament.
Used well, an archetype is a tiebreaker rather than a foundation. Do the specific work first. Who you serve, narrowly enough that somebody could be excluded. What you claim, in terms that could be wrong. What you refuse to do. The sentences only you could write. Then, when two acceptable options remain and neither is obviously better, the archetype tells you which is more like you. That is a real function and a small one. If you want the framework's value without its ceiling, write a described position in your own words and keep the archetype as a single line at the top of it, where it belongs.