Each day you log in, you can loot a sign in bonus chest. The rewards will increase each consecutive day that it is opened, however the quality will reset if you miss a day.
Heroes
After collecting a required amount of soul stones you will be able to summon a certain hero and use them in battle. Manage your heroes strategically by equipping them with all six necessary equipment slots in order to promote them. Promoting a hero gives it more power and unlocks a new skill.
Skills
After your party reaches level three, you can increase your heroes' skills. Upgrade your hero's skills to boost their fighting ability. Upgrading your skills will result in a very noticeable improvement from your previous damage, or healing rate for healer types. Gold is required for the upgrades, with costs progressively increasing. Each hero has a super skill that must be charged with energy before it can be used. Energy is obtained by inflicting and receiving damage.