Narvarn Steppe is an intermediate grind-zone. Narvarn mobs are primarily grinded for the infinite mana pot. The way the mana pot piece is obtained here is by gathering from dead mobs it cannot be obtained by looting the mobs. The infinite pot allows you to infinitley replenish you mana without ever having to buy mana pots. The xp here is super low. With that being said, this spot is sub - par, you can grind Polly's for better, more profitable rewards. Polly's is also one of the best spots in the game for xp.
Narvarn Steppe is located east of Grana; Grana is located South of Calpheon, the third major city in Black Desert.