General aviation pilot reported a NMAC during departure with an aircraft that descended on top of them entering the traffic pattern. Pilot took evasive action to avoid a collision.

Narrative

I was departing Runway five at ISO en route to ZZZ which requires a left turn and an aircraft was entering the left downwind for Runway 5. ISO Tower told me that I could take my left turn to ZZZ too early and the other aircraft descended into the downwind as I ascended to my cruising altitude. The other aircraft would not stop descending into the downwind and used ZERO radio calls or ADM to see/navigate away from me on the ADS-B. I saw his icon go from +04 (400 ft above me) all the way to +01; and I called Kinston Tower to tell them I had traffic converging and he almost disrespectfully told me to take evasive action absolutely not aware of how close this could have been to a double fatality. The only reason it was not is because I pitched the nose down and started descending away from the converging aircraft which brought my airspeed into the yellow at about 130 kts. while I was around 800-900 feet above the surface. Complacency from both the other pilot and controller caused this; at the end of the day it is the pilot's responsibility to make responsible and safe ADM; and that was not done at all and my evasive action is the reason I am typing this and not in the news for an aircraft collision. I got zero alert from the TCAS but I used the ADS-B altitude reporting to take this action.