History of Coven Down

Coven Down is a 10-point The Wellspring triumph: on the Attack day, defeat all 3 Witches within 20 seconds of each other.

How to complete

1. Run The Wellspring: Attack (the Attack rotation, not The Wellspring: Defend).
2. In the final boss fight, you charge three plates to break the boss's shield. Named Witches spawn in the arena and killing them breaks the shield again (Screen Rant).
3. The triumph needs all three Witches dead within 20 seconds. Neither guide gives exact timings, so this is a suggestion: let them accumulate, then kill them together with your fireteam, rather than one at a time.

Seal

Shacknews lists it among the Wellspring triumphs in its Gumshoe guide but says it is not one of the required triumphs for that seal. No other reward is documented.