Divine Halberd of Poseidon is a two-handed level 100 treasure axe. This weapon can not be crafted or upgraded, it can be found by searching treasure maps. Additionally, it is available as a drop from an instance.
It can also be found by searching level 4 treasure maps.
Divine Halberd of Poseidon is used as a crafting material for Black Dragon Battle-axe and Cutting sky battle-axe. It can also be exchanged for Exact Apparatus at the Antique Collector in Barcelona City