Peel mango. Slice fruit off each side of pit and dice. Spoon mango and juice into bowl. Stir in diced red pepper and red onion.

Rinse blackberries. Remove ½ cup berries and set aside. Mix remaining berries with mango mixture. Pour into processor and pulse two or three times. Scrape back into mixing bowl.  Taste. Add agave if you want it a little sweeter. Stir in remaining berries. Chill.