Domains: Frozen waste, hook-and-line survival, the catch hauled up through the ice without certainty of what was caught.
Era of ascension: Great Expansion (~4,500 BSD). Cohort: current. Frostgrim rose with the Hookling settlement of the deep-cold lake country, when the halflings who had followed the ice-edge north found that the hook-fishing tradition they had brought from the green-water lakes carried no patron capable of recognizing the kind of dark water they were now fishing.
Worshipped by: Hookling ice-fishers, the hook-grinders who maintain the cold-line hooks (a specific style with a backward-curving barb that the Hookling refuse to share with outsider fishers), the keepers of the haul-tallies who record what comes up from each season's holes. Hookling does not share Frostgrim with the other halfling peoples; the deep-cold lake tradition is geographically specific and the worship has not spread. (The worships edge is authored downstream on the worshipper, not here.)
Frostgrim is the daemon of the haul. A Hookling ice-fisher cuts a hole through the deep-cold lake-ice in midwinter, drops a baited hook through the hole into water that may be sixty feet deep and dark all the way down, and waits — sometimes for an hour, sometimes for a day — for something to take the hook. The hauling-up is the worship. What comes up is what Frostgrim has decided to send. The Hookling do not assume the haul will be a fish; the deep-cold lakes hold a wider catalog of living things than the green-water lakes do, and the Hookling have a tally-vocabulary of seventeen named categories of haul, of which fish is only one and the most common.
The categories the haul-tally records include the ordinary cold-fish (most hauls), the long-eel (a smaller percentage but expected), the white-fish that cannot be eaten but is rendered for oil, the ice-thing (a category that covers several creatures the Hookling do not bother to distinguish further), the empty hook (a haul Frostgrim has refused, taken as a sign), the broken line (a haul Frostgrim has refused with prejudice, taken as a strong sign), and several categories the Hookling discuss only among themselves and which outsider fishers are not told the names of. Hookling doctrine treats the haul as Frostgrim's answer to a question the fisher has been asking with the act of fishing. The fisher who has caught nothing but empty hooks for a season is held to be asking a question Frostgrim has chosen not to answer, and the elder fishers will sometimes counsel such a fisher to change the question.
The lore-handle Hookling hook-grinders carry, recited at the sharpening of a new cold-line hook, is: the hook does not ask what is hungry below; only what is willing to come up. The doctrinal corollary is that a Hookling fisher who has hauled a thing they did not want has been answered honestly — Frostgrim has sent what was willing to come, and the fisher's refusal of the catch is a refusal of the daemon's answer, which is allowed but is not free. A fisher who has refused too many of the daemon's answers, the elder fishers say, will find the hole closes against them; the ice grows back faster than the fisher can keep it open, and the season ends short.