For friendship coupons, you can and should buy a 4-star bow "Ode to Anemonia". During the Holiday, you can pump with a bonus of x1, 5. The Visible Wind item is needed to awaken the bow. The chains of the lion's fang are needed for elevation. The number is limited, so you will have to feed in the dungeons to level up to level 90. General advice: buy everything that is bad in stores and swing.