This is Philia Felice's Swordian. The personality written inside the weapon is that of Laville Clemente, one of the E'rther Army Chiefs of Staff from the Aeth'er Wars.
He was sunk to the bottom of the ocean with the former E'rther base Radisrol when the Aeth'er Wars ended. He stayed there till he was found by Philia and the rest of the party. He is a jovial person, but also fair and insightful. He is the leader of the Swordians.
In melee combat, Clemente is a hindrance, due to his low attack power. However, he commands a large repertoire of powerful spells from all of the elements, not just his own personal element of lightning.
