Hi! I decided to open a sketchbook here to push myself more into sharing my work.
I’m a Game Art student, currently in my last semester, and still rather new to VFX. I’m looking to improve my skills to become a professional real-time VFX artist.
Feedback, ideas and inspiration would be much appreciated! And of course don’t hesitate to ask questions 
Starting with my most recent WIP; A Slash VFX made in Unreal Niagara:
That’s a really good beginning!
I would say you already have a base and now it’s mostly about adding additional elements to make it look full!
Design Process of ‘Fire Slash’ VFX – HeyYo CG ← this might be a good source of knowledge for you btw 
So…
Right now the slash itself looks a bit plain + it doesn’t feel as impactful yet.
I would start with adding some elements that would add some volumetric look to it (like smoke, some kind of emitting energy. You have those little sparks, but they don’t really fill the shape + they move in the opposite direction. They should inherit movement from the swing rather than go the other way (it takes away from the power of the swing)).
I would also add some kind of a glow with each hit that would lighten upa the environment a bit around the character. This way it would feel like it’s a bit more grounded in the world.
I will be happy to give some more feedback afterward!
Good luck :3
btw, such a cool frog pfp XD