In the manga and an SBS, Davy Jones is spoken about as the legend of a lying, greedy, and notorious pirate who once lived in ancient times and was cursed by a Demon or the Devil to eternally remain in the deep sea (seafloor).
Xebec worships him, and pirates view Davy Jones's Locker as a form of fated punishment for disgraceful pirates. This is their pirate version of Hell. As for the Devil who cursed Davy, it's easy to draw a connection to Imu.
So, who is Davy to Imu? Davy's insatiable greed may have eventually peaked as a desire to become the King of the World and thus directly challenged Imu in the process. If Teach inherited Xebec's will, then maybe Xebec himself inherited Davy's will.
What's interesting is that Davy Jones is believed to be immortal, like Imu, and is said to take in all sunken things. The latter aspect mirrors the concept behind the Yami Yami no Mi. In the deep sea, there's no light; only darkness. The gravity of the depths exerts crushing water pressure, akin to a black hole. Maybe the Yami Yami no Mi is the key to liberating Davy from his cursed fate. Its Awakening could allow Blackbeard to use existing darkness to manifest his Black Hole technique in those depths and then use his Liberation technique to free Davy.