V.E Schwab 
Shades of Magic [PDF ebook] 
The Steel Prince #2

Decades after the worlds have come apart, Red London is peaceful and thriving under the Maresh Empire. Believing that one day the magic separating the different worlds would come undone, Prince Maxim is searching the land for powerful magicians who can travel between those realms. Frustrated by his son’s negligence of their own kingdom, King Nokil banishes Maxim to Verose, also known as the Blood Coast, to redirect his focus. Upon his arrival, Maxim encounters rough bandits, hoodlums, and worst of all, the unruly soldiers of the royal military. However, his troubles don’t end there, as a ship with a dangerous looking crew has docked at the harbour…