Tshira Ruins is an intermediate grind-zone. Tshira mobs are primarily grinded for the infinite mana pot. The way the mana pot piece is obtained here is by looting dead mobs. The infinite pot allows you to infinitely replenish your 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.
Tshira Ruins is located east of Duvencrune; Duvencrune is located South of Heidel, the Second major city in Black Desert.