Unfathomable: From the Abyss

You can rescue each passenger in your space, or one passenger in an adjacent water space. If you rescue multiple passengers at once, spawn only one ally for that rescue (p. 4).

You may use an ally in your space before or after an action by discarding skill cards whose total value meets or exceeds the ally’s cost. Each human can use only one ally per turn, unless an ability specifically allows additional allies (p. 5).

Usually, no: when a horror would be defeated, it is repelled and moved to an adjacent space; you may discard skill cards totaling 4 or more to move it one additional space. Only the travel track or ritual track can defeat a horror and remove it from the board (p. 7).

If there are no horrors on the board, advance the horror track; when its token reaches Spawn, draw and resolve a horror card. If one or more horrors are on the board, the icon activates a horror instead (p. 7).

No. A player cannot perform a space’s action ability while a horror is in that space (p. 7).

Boons always count positively as supporting skills. Treachery cards can be added to checks, but only revealed traitors can use their abilities (p. 8).