Revenant Splinter Knuckle is crafted with Blacksmithing in Mabinogi (weapon). This page lists everything needed to make it, checked against the game as it exists today. The interactive planner lives in the Blacksmith Companion.
How to get the manual
The manual is rank 7 and survives 30 uses; every crafting attempt spends one use.
Gilmore: general shop owner in Bangor, sells them at his counter (200,000 gold).
Materials
Expect about 4 attempts per finished item (25% average progress per attempt). Per-attempt materials are consumed on every attempt; finishing materials once per item.
Each attempt uses
3× Gold Ingot — refine from 5 Gold Ore
3× Mythril Plate — re-refine from Mythril Ingot
1× Vengeance-Imbued Blade — Hard Tech Duinn missions drop
Finishing (once per item)
3× Gold Ingot — refine from 5 Gold Ore
7× Large Nail — hit props (lamp posts, signs, statues) or common low-level monster drops
1× Tough String — weaving Thick Thread Balls
1× Misty Red Gem — Tech Duinn hard difficulty mission drop
1× Sealed Strength Crystal: Knuckle — fragment a high-rank knuckle (Demonic Solitude/Shyllien Mana/Stigmata Knuckle)
1× Sealed Strength Fragment: Knuckle — fragment a Bracer Knuckle or Champion Knuckle (basic blacksmith-shop knuckles)
1× Sealed Strength Powder: Knuckle — fragment a basic shop knuckle (Bear/Hobnail/Spiked Knuckle)