During your journey, you will encounter many different characters who will probably turn into powerful allies. Most of the time playable characters and weapons are unlocked through so-called wishes. Wishes can be bought using primogems which are awarded after certain quests, or they can be bought in exchange for real money. As of right now, there are 50 playable characters and each one comes with a unique weapon (either a bow, sword, claymore, polearm,, or catalyst). All of them have their own Stella Fortuna, that serve as Constellation Activation Material items, which can be used to unlock Constellations and can make your characters even more powerful.
Before striving through the lands, you should consider building a strong party to be prepared for the dangers awaiting you. A party consists of up to four characters. Each character has a certain elemental skill, which will be used in combat.