Good question! It basically hovers there like a giant energy receptacle, existing both as a power and as a vulnerability.

If and when there is a clash between the King (or, in this case, the god) and an equal power like that of another King, the Sword will show signs of shielding itself. However, the Sword cannot withstand high-powered direct attacks (like a lightning bolt), and damaging the Sword increases the likelihood of it falling, which may cause destruction equal to that of a nuclear bomb. :c

So the Sword's appearance is kinda ominous.