Help with advanced vfx

If you look at Hours by @superrun100 , it has some incredible vfx that go beyond what most youtube tutorials teach. I want to know specifically how they made the simple sword swing effect for the character you initially spawn with. It seems to be a few sqaurish planes stuck together, but I wanna know specifically how you could implement it. Additionally, I’m interesting in several of the light attacks the bosses near the end of the game do. They seem to be spherical beams, but I’m interested in how it was done. If you know, or know something similar and it’s implementation details, please let me know.