Spirit Breaker Charge of Darkness VFX Question

Making a charge effect and a peer-recommended I to look at Spirit Breaker’s charge. My main question is when I’m looking at the trail left behind the character it seems like it’s a ribbon orientated along the Z-axis (up and down), but when I look at it in a more dynamic view it has a conoidal shape from the character and tapers off. Is there a small particle placed at the top of the ribbon to create that more dynamic look?

Static View - Spirit Breaker - Charge of Darkness (Creeps).wmv - YouTube

Dynamic View - Dota 2 Hero Spotlight - Barathrum the Spirit Breaker - YouTube

Just having a hard time wrapping around what is happening here and any help would be much appreciated! Thanks all