In Triagia, it is not possible to transfer items between characters other than through the market. When you take, steal, or otherwise obtain an item from someone else, it will be marked as stolen:
Stolen items cannot be used and cannot be sold except in trade wars. The stolen mark is cleared when the items are returned to their owner or placed on the ground.
Loot
When you kill a monster in a group, you can split the loot inside the corpse. The owner of a looted item is set when it leaves the corpse.