Mythril Barbut

Taken all the way down to base materials, one Mythril Barbut is 3 crafting steps deep and needs 5 intermediates — Mythril Plate ×1, Mythril Rivets ×1, Steel Plate ×1 and 2 others — which resolve to 3 distinct raw materials totalling 18 units, plus 41 crystals.

That bill outweighs 7,380 of the 13,602 recipes tracked here and 694 of the 1,441 Armorer ones, and 337 recipes nest deeper.

Only 9 of those crystals go into the final step; the other 32 are burned by the intermediates, so the real crystal cost is 25 Fire Shard, 12 Ice Shard and 4 Earth Shard.

The chain crosses two disciplines — Armorer to Lv 41 and Blacksmith to Lv 39 — so no single class can finish it unaided.

All 3 raw materials are gathered, and not one of their spots is timed, so nothing in the tree waits on the Eorzean clock.

Of the intermediates, Mythril Ingot has the widest use: 135 recipes call for it, spanning seven of the eight crafting classes.