Abyssal Robe (F) is crafted with Tailoring in Mabinogi (robe). This page lists everything needed to make it, checked against the game as it exists today. The interactive planner lives in the Tailoring Companion.
How to get the sewing pattern
The sewing pattern is rank 1 and survives 30 uses; every crafting attempt spends one use.
Rundal Advanced Hardmode / Veteran Dead-End Chest Reward: Run Rundal Advanced Hardmode and open the hallway dead-end chests for a chance at Destructive gear sewing patterns.. Enter through the Rundal Hardmode Dungeon altar; Peaca Veteran's own dead-end chests do not carry these patterns.
Materials
Expect about 1 attempt per finished item (99.9% average progress per attempt). Per-attempt materials are consumed on every attempt; finishing materials once per item.
Each attempt uses
1× Void Robe (F)
1× Destructive Crest — Craft it using the Handicraft skill.
Finishing (once per item)
5× Finest Finishing Thread — Buy directly from any general goods NPC shop.