Vito Crux Armor is crafted with Tailoring in Mabinogi (armor). 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 6 and survives 30 uses; every crafting attempt spends one use.
Giant Alligator: Defeat the Giant Alligator field boss in Irai Ruins in Courcle.. Spawns only in set daily windows, all pets and partners are dismissed on approach.
Materials
Expect about 5 attempts per finished item (20% average progress per attempt). Per-attempt materials are consumed on every attempt; finishing materials once per item.
Each attempt uses
2× Fine Fabric — weaving on a loom, low rank
4× Iron Plate — refine from Iron Ingot (re-refining)
3× Fine Leather Strap — weaving rank 6 on a spinning wheel
Finishing (once per item)
1× Fine Finishing Thread — Buy directly from any general goods NPC shop.