Where to get it
World Great Yokai (red and orange), Seek the Blade with a party, auto-battle, the Foreign Lands (Shadow Gear), Shinkiro.
Enhance
Enhance in the Forge with coins. The level is never lost, and milestones add bonuses.
Devour
From Lv. 71 spare gear goes into Gear Devour. Do not hoard junk.
Gems and refine
Gems go in by slot and tier. Refine (Lv. 200) and Reforge (Lv. 260) change and boost stats.
Divine Gear
From Lv. 160 keep your orange 2★ pieces: they synthesize into red Divine Gear.
Resonance
From Lv. 240 seal Wildlands great yokai for resonance stones.