Hillwen is crafted with Hillwen Engineering in Mabinogi. This page lists everything needed to make it, checked against the game as it exists today. The interactive planner lives in the Hillwen Companion.
Recipe availability
Hillwen is a rank N Hillwen Engineering recipe with a best success rate of 98% at rank 1 and dan ranks.
Materials
Each craft uses
5× Hillwen Ore Fragment — Rare Mineralogy at the B3 Type 2 deposit (100% success, 67% fragments, 500 per node); Seal Merchant Mondays 50 for 5 seals