Gems are rewarded after the completion of each arena trial. They can be used to enhance the weapons by unlocking more ability slots and new abilities at regular intervals. Each trial contains three gems as a reward. The first requires completion, the second is a specific challenge and the third is a time trial. If the arena boss is too difficult, it is possible to complete all these challenges to earn extra gems. "Forced" has a Mark Combat System, where weapons cause marks on the enemies. A greater number of marks causes certain abilities to have better effects, thus making it more effective to hit a group of enemies a few times before using an ability, rather than using it at the start. Though the difficulty increases in proportion to the number of players and sharing Balfus needs communication between them, multiplayer is easier and lets the player focus on specific abilities and tactical roles instead of being forced to cover every possibility in single player; also, if a player dies, the trial can be completed as long as another survives till the end.