@TruckKunHere are some weaknesses that I found on a superpower wiki.
-Distance, mass, precision, etc. depend upon the knowledge, skill, and strength of the user, and their power's natural limits.
-Light Manipulation, Light Generation, and other light based powers are especially effective against this power.
-As shadow is a dark area produced by a body coming between rays of light and a surface, light may strengthen shadow magic or may even be a requirement in some universes.
-May be unable to create darkness/shadow, being limited to manipulating only from already existing sources.
-May have to be in sync with darkness, whether their own or the source of their power.
May become affected/corrupted through extended exposure.
Umbrakinetic Immunity/Shadow Absorption
I am unsure if any of these will help you, but i do hope it does. As for names here is a website i use for name generation.
https://www.name-generator.org.uk/?i=26xn2aix 
