This melts big bosses

Underrated. I accidentaly used this against a pack of dogs in mohgwyn area and it shredded them. Of course it works best against big creatures, but its still ok otherwise

Comet and Spiral is best spells in game.

Casting Collapsing star after shard spiral is definitely a KEK moment for the enemy

Alongside Comet Azur, this is one of the best spells in the game.
Getting close and spamming spirals simply erases large and mid-to-large slow-ish bosses (dragons, tree spirits, fire giant, Astel, ect).
Still a a bit situational: you have to get close, you have to have enough stamina to be able to pull off several casts, the boss has to be distracted by the summon and not about to jump away or slam you.
That said, it doesn't work in all cases. E.g. you're gonna get stomped if you try this with hyperaggressive and fast bosses like Maliketh, Malenia, Godfrey.
As with everything - gotta know when to use it.

Sellen's master Azur studied comets and made Comet Azur, so I suppose Sellen made this spell in attempt to create comet of her own. Kinda sweet actually, and very powerful against large bosses.

This is basically the best spell in the game. It works in basically any situation: single target and AOE; far and near targets; normal enemies and bosses, etc. Remember that you can charge it for harder hits. It's carrying me through the games and toughest bosses.

This spell is extremely good against large targets as it keeps on hitting them as it moves. I used it to fight Placidusax and it was so effective that he never even got to teleport a single time, died right on the spot where he starts the fight without even moving. It's quite good against Elden Beast for the same reason.

It's pretty nice against smaller targets too, it will still get multiple hits as it passes through a target and although it doesn't reach the crazy damage it gets against big foes it still has pretty good FP/dmg efficiency since it's fairly cheap at 14 per cast. The main disadvantages are that it doesn't have the best range (not terrible either) and that it moves slowly. Tracking is good, but the slow projectile speed can be a problem.

wait wait wait... was the karalos conspectus's idea to make a new comet literally just to stitch 2 glintstones together? for a bunch of wizards these guys really have low intelligence dont they

I made it all the way to Elden Beast before I realized that this spell hits multiple times per cast, and is perfect for massive Bosses. This whole time, I'd been relying on the slower Comet Azur to get opening damage on it. Switching to light attacks with the Dark Moon Greatsword, Shard Spiral, and Carian Slicer made the fight significantly easier. Even if Shard Spiral wasn't nearly a one-shot, and most of my damage came from Slicer, it was a VERY helpful tool to get off some damage and then keep moving. If I'd used the same FP to walk around casting Glintstone Pebbles, I'd have to sprint WAY more to catch the Elden Beast. Thanks to the Shard Spiral doing damage WHILE I moved through the Arena, it was way easier to keep close to it, letting me use more Slicers and dodge more Sacred Blade attacks.