Chief Gear Priority
Chief Gear has 3 parts: TOP (Lancers), MIDDLE (Infantry), and BOTTOM (Marksman). Upgrading in the right order saves massive resources and gives the biggest combat boost.
Always upgrade FIRST and keep highest
Infantry tank for the entire march — your survival pivots on this slot.
Keep CLOSE to Infantry (same lvl if possible)
Your main damage. Match Infantry level when resources allow.
Keep 3–5 levels BEHIND the rest
Least important — don't waste resources rushing this slot.
Top slot = Lancers, middle slot = Infantry, bottom slot = Marksman. Use the layout in your Chief screen to confirm which slot is which before spending materials.

Infantry absorb damage for your whole march. A weak middle slot means your Marksman die before they fire — gear them up first to keep the formation alive.
Marksman are your damage. Once Infantry is solid, push Marksman to match — same level is ideal, one tier behind is acceptable.
Lancers are flank/support. Keep this slot 3–5 levels below the others — the resource savings let you snowball Infantry and Marksman much faster.