Sylph is a healer class. As such a healer of time would have abilities very similar to Bleach character, Orihime Inoue. This means you could literally restore complete limbs by reversing time around a severed arm! This ability is extremely helpful, especially if someone has died
I think if you were to use your abilities on someone who has died within a specific time limit you might be able to restore their life for them! But doing so would put an enormous strain on your own body, so use it wisely!
Your land would be an immense cityscape full of pure black matte, iron spires and towers. Gears are main components of buildings and the centerpiece of the land is an enormous elaborate clock tower. The spires look like the come straight from a fantasy world full of spikes and swirls.
The second thing that comes to mind is that ebony makes me think of pianos, so maybe there are many concert halls playing all around the land too!