So I'm having trouble finding catalysts to break through artifact levels. I'm specifically looking for Dionesium. I completed the League of Assassins from the On Duty Menu as Green Lantern. I went through the entire Scenario and beat the boss with 3 others, but didn't get anything from it. I can't choose this scenario anymore, so I'm not sure where to go from here. Can someone tell me what I'm doing wrong? Thanks.
When mentioned Green Lantern that caught my attention. I think it needs to be done in the tier 3 alert.