Completing the Trials of Ascension is vital as it supplies you with important materials to increase the level of your Heroes! As you and your Heroes become higher level, you will need to earn more and more resources to make Heroes truly elite!
When you are picking your Trial, make sure to pay attention to what kind of Heroes you should bring! For example, Mimir is particularly susceptible to AoE Damage, so using Heroes like Zeus and Lucifer will be great choices. Then, when fighting the Genie, Heroes that do magic damage are best. In this case, taking Lucifer with you won’t really help, but Zeus will!