My deaths so far have been from:
Death 1: Walked a bit too close to the DEATH POTION spawner at the start of the Lush Ruins.
Death 2: Zistykin punched me off the edge into lava. Threw a pearl, but didn't hit anything in time.
Death 3: Well, in Zisteau's cavern in Intersection 3, I saw the TNT in the center house... and thought it would be fun to set it off. The cavern, along with me and my items, exploded into nothingness.
Haven't started the second half yet, so I imagine more deaths await me.
Also, screw your thornguards, Vechs.