Duty to a Melody

Augustus, a Sternguard Devastator from the Ultramarines, is sucked into a warp rift and dropped right in Equestria! His body changed from the might demi-god Astartes, to a somewhat muscular unicorn stallion. With no way of figuring out a way back to his ship, the veteran Astartes decides his best course of action, would be to try and "blend in"... Running into a certain chellist to help him with this.

Can this Son of Guilliman find a way for him to keep his cover from the entirety of Equestria? Will the Chellist find out the secret behind this intellectual Unicorn Stallion, who enjoys her very passion? Well then, let us hope things go well... Before a certain Centaur returns to wreak havoc upon the innocent masses of Equestria once more.