The will-o-wisp's signature effect: a 4th-rank+ Darkness that fills the room, blinds even dark-vision users (targets concealed/hidden), and — uniquely — interrupts and drains the party's spellcasting at the source while it persists. Must be counteracted by an equal-or-higher-rank Light spell to target the wisp. The concealed-vs-hidden interaction in this darkness drove a long table rules dispute.
Most recently recorded in S55.
No open hook is currently recorded.
No open hooks are currently recorded.
No player-visible relationships are currently recorded.