Hi, you can check the forum for the current black market item each weekend (black market sells items).
If you're looking for a golden hero, you can try the card forge, there's a chance to gain an expert card from it.
If you've beaten golden grounds, you can forge expert cards for 400 relics.
What hero card you're after?
If you mean Lucian, the new hero in the DoL season, then you need to beat Dawn of Light map.
Edit: Fixed the map from golden grounds to Dawn of Light. Not sure why I typed that.
Really? I got him after beating the dawn of light map i think. At least I have him and have not beaten golden grounds yet
You have to beat the new Dawn of Light map to get him.
My brain somehow subsituted 'golden grounds' with 'dawn of light' in FuzzyEuks answer.
Dang!
Thanks Kami for clarifying.