A custom-made Sword for my Warforged Spheres of Power Magus Character I recently put together and played the first session of.
Spheres of Power is a system where unlike normal D&D and such where there are a handful of different schools of magic, there are instead 20 very distinct "Spheres" of magic. And unlike a normal caster that can basically just take whatever spell they have available to them, a Spherecaster can take virtually any spell no matter their class, but they must learn a sphere in order to gain access to that sphere's powers. In essence it encourages focusing on a few specific types of magic and being really good at that over branching out and being able to cast anything.
Relic, my Warforged Magus, is as his race implies, a creature that was created for the purpose of battle, an experimental prototype that specialized in efficiently allowing himself to be able to cast spells and attack with traditional weapons in quick succession. His magical energies are built directly into his adamantine body, allowing him to cast directly off of his constitution rather than through study. A downside of this is that casting spells slowly drains his energies, so while he is incredibly tough for a caster, which helps him survive the front lines, Using too much magic in a short time can overload him. Unfortunately, as he only became sentient shortly after the war he was made for had ended, the flaws were never able to be worked out from his body.
Recognizing that he was a machine created for a purpose no longer needed, he spent many of his years simply wandering the world and exploring, purely out of curiosity to see what awaited him outside of his intended purpose. However at his core he does still love to battle, occasionally challenging local champions to bouts or helping take down local troublemakers, purely for the sake of the fight. But despite this he usually doesn't get himself into too much trouble, having a strong sense of honor and being unlikely to strike first unless wronged in some way. He has few friends due to his wandering nature, but those he does consider friends he is extremely loyal to.
The Magical Spheres that he was designed to possess and control were the Destruction, Protection, Time, and Warp Spheres. Specializing in Electricity-based magic he uses Destruction as his primary Offense, and Protection to ward off his enemy's attacks with helpful Aegises. The other two spheres were the most exotic and experimental parts of him, able to be used offensively or defensively depending on any number of factors. The Time Sphere gives him power over the local flow of time, able to speed himself up and slow down enemies, even stopping everyone in their tracks when needed. And the Warp Sphere allows him to bend space to his whims, granting the normally slow and stoic pile of metal surprising agility as he simply teleports from foe to foe, avoiding attacks along the way.
His sword is part of what allows him to control these spheres, acting as a sort of focus to help contain the arcane power. Sheathed in a slot physically built into his back since his creation, it is in many ways literally a part of him, and it has much potential that is yet to be unlocked, but over time as he learns more about his own capabilities, so to will his sword grow in power and allow him to become stronger and take down ever greater foes.