Who focuses a breach with Brane Knife?

Name
Who focuses a breach with Brane Knife?
Details
Unlike most focusing relics, Brane Knife (Gain 1 charge. Any ally focuses their closed breach with the lowest focus cost.) allows an ally to focus one of their breaches. Typically, focus relics allow the player to focus an ally's breach. This distinction may be relevant when evaluating focus effects.
Cards
Brane Knife
Mages
Nemeses
Other
Legacy Chapter 2
References
https://boardgamegeek.com/article/31099055#31099055