Ruathey gives this item to collect and combine quest contents to form Ghoulbane - The item reward for completing The Sword of Nobility quest line. The name of the container is "Nobleman's Bag". It is a Large item with a 4 item capacity and a Large size cap. It includes a combine button to combine the Ghoul's Heart, Amstaf's Scroll, Blade of Nobility, and the Nobleman's Hilt to form Ghoulbane.
Ruathey is still located where she is listed on her page, in Lavastorm Mountains: 603, -7, 103.
Unless this item is obtainable from any other NPCs or mobs in the game, then I'm not sure that it qualifies as "Common" rarity. The level to attain it would be whatever level it takes to attain it from Ruathey. I'm not sure if there are level restrictions to obtain it from her.
I just obtained this bag from Ruathey last night. I will update this comment when I have acquired all the quest items and attempted to combine them.
Edited, Feb 25th 2015 1:07pm by Omnicronimous