Alright ! 
It does look like a dark lux ult
You could try to make some of the elements start faster and slow down over time, to have more of an explosive feeling. Depending on what engine you use, you could use drag to create that kind of movement.
I like your choice of colors, but not the way they interact. It feels like both colors are fighting for dominance which creates a lot of contrast, but it lacks coherence.
The dominant color in all blood moon skins is dark red. So this should probably be reflected in this skin aswell.
You could try to make the laser fade to streaks of dark red after it fired, and make the runes which linger, small lean glowing blue runes?
The first beam of the ult (I think the one used in game to signify theres something coming) should be smaller in my opinion, or less fussy. Maybe you could add a pattern to it to make it more interesting?
I do like the impact of the laser itself. It feels strong and impactfull. I can easily know as a player that I shouldn’t stand in that.
I like the runes which are visible after the laser. Altough after doing some research they don’t really fit with the theme of the other skins (Unless theres some skins I haven’t found). I feels like you went for some hybrid between bloodmoon and arcane. (Which I think is really cool, so in my opinion you should keep the runes )
Most of the bloodmoon skins too me feel like this kind of color palet. (Mostly dark red, with the highlights being a different color).
These are kind of the skins I looked at.
Anyway, I think it looks really cool, keep up the good work