One of the most important things about playing Dynasty Warriors is increasing the power of your character. To do so, you will need to obtain better gear.
The best weapons in Godseekers are earned from chests, which are acquired both from completing a mission in addition to being found in the game world. Chests earned at the end of a mission are randomized, and therefore completing as many missions as possible is one way to earn great gear. Alternatively, you will want to explore the map for chests, preferably the rarer black chests.
There are many different rarities of weapon, the best of which being legendary. As you play longer, and perhaps get lucky, you will find these more often.