
Originally Posted by
Tokitoki
You got a 5* from your regular daily draw only a week in? God I hate you.
Anyway, upgrading is really easy. In the "Equipment" menu select Upgrade Equipment. Select the item you want to upgrade (in this case your Danjuro and Variable Steel are your best options). After you select the item to upgrade your inventory will be pulled up again. You can select items from your inventory to "feed" to the weapon to increase its level.
In general, feeding other weapons and armor is not very gil-efficient. Scarletite is for weapons, Adamantite is for armor. If you use them for the correct type of equipment you get a bonus amount of exp towards the next level.
For each "tier" of equipment you get additional bonuses when that weapon has Realm Synergy. I believe these tiers are every 5 levels (1-5, 6-10, 11-15, 15-20, etc.) and will add a set bonus when you're within each range.
In addition to the bonus from realm synergy, the higher the base star level of the item the stronger they will be (which I'm sure you figured out). A 3* item that has been combined to the 5* level will be weaker than a natural 5* equipment. There are some changes to this based on Realm Synergy, but it is a good rule to follow in general.
The other option, once your weapon is at the maximum level for the star tier, is to combine two of the same item to upgrade it to the next star tier. In this case only upgrade one of the items to the max level (say 15/15 for a 4* equipment). The other one should be left at the base level so as not to waste gil, materials, etc. The disadvantage is that you will lose the weapon you are "Adding" to the combination. If you are low on synergy equipment for that realm, and it's a decent tiered weapon (4*/5*) you may want to save both and upgrade both to use rather than combine and only have 1 weapon.