Vá até o NPC Bram (não tem auto rota) que fica atrás do NPC Bianstimi, dentro de uma casa. Nele terá duas quests. Acho que pode escolher qualquer uma das duas, mas eu escolhi a Faltam materiais, que requer 250 lingotes de estanho e 250 pós da escuridão. Completando você ganha um Baú Misterioso Surrado, que pode vir alguns acessórios e também o Restos do Baú Misterioso, que é usado para completar a quest. Caso venha o acessório ao invés dos restos, não sei como prosseguir, mas talvez dê pra pegar a quest de novo.

เลือกรับเควส วัตถุดิบไม่เพียงพอ ส่งมอบ แท่งดีบุก 250 + ส่งมอบ ผงความมืด 250 หรือ เลือก ล้างแค้ให้ข้าหน่อย ไปกำจัดแมกีแมน 1000 ตัว

Behind Bianstimi in Calpheon there is an NPC called Brahm.
He will give you a quest that requires 250x Tin Ingots & 250x Powder of Darkness, which will give you a Shabby Mysterious Chest.
Roulette will give you Remnants of Mysterious Chest, give it to Rubin and done

You can also buy Mysterious Chest from Lara and open to get the remnants(recommend to buy the earring chest)