The aqua warblade was a bladed weapon that served as Hewkii's Toa tool when he was a Toa Mahri.1, 2, 3, 4, 5, 6, 7, 8 Hewkii could use it to channel his elemental power of stone.CN It did not have any additional abilities; it was simply one of the finest swords ever made, designed for use by a master warrior, which suited Hewkii in combat.4
Hewkii acquired the aqua warblade when he was transformed by the Mask of Life from a Toa Inika into a Toa Mahri. Presumably, his former laser axe was transformed into the aqua warblade.CN Hewkii presumably continued to use the aqua warblade on Spherus Magna.CN