Grand Chase Dimensional Chaser/Farm Prana

Sell Heroes
Selling 6☆ S and A rank heroes on Friday for a 10% chance of gaining 2x prana and prestige marks is the most efficient method of gaining prana. Upgrading B rank heroes is not recommended because of high Monster Card and Evostone usage with little return. Fusing 6☆ +9 Heroes is recommended to minimize Evostone usage. Fusing A+S 6☆ +9 Heroes During Hot Time is also a viable option. Chance of getting an S hero is about 50%-60%. The percentage is derived from personal testing of 12 total fusions. (Requires more testing)

Wizard Labyrinth
Priority should be 1) S Rank Hero 2) Prana 3) Monster Card/Gold

Request Coin Shop
Another way to gain Prestige Marks is via the Request Coin Shop. (Need input on efficiency. Not known if it's recommended to buy Prestige Marks this way)