I am now using Moonveil Katana maxed out, and thanks to the person who recommended Ranni's Dark Moon. The R2 + R1 and the R2+R2 on the Katana are both the most powerful moves I have right now, and that includes the whole Azur's Comet setup from earlier. I never realized the whole time my mage was being built around a sword, lol. The Moonveil Katana melee makes most of the game a joke, especially phantoms. I'm not sure if it is like this for other weapons, but the weapon art on Moonveil is incredibly overpowered compared to normal swings. Like beyond incredible. Get the "none" power for your carion shield and you can cast both weapon arts without having to 2-hand it, and it just destroys everything compared to any power I've had the entire rest of the game. It's faster, more deadly, and better than any spell I got. Lemme tell you one more thing, Radagon's Soreseal with this weapon on a mage is so synergistic. It scales with int, dex, and str, of course I have relatively low dex/str but 60 int, so Radagon's bumps that str/dex level enough to be considerable while I'm effectively soft capped maxed on my int, at +10(I couldn't get to +10 until after the giant since the stones were out of reach, but I didn't look too closely, +9 was plenty) the fast draw technique using L2+R2 is so, so fast, head seeking, ultra damaging, and just unfair.
I beat the fire giant right after clearing the capital(he's basically very resistant to magic, so I just spammed L2+R2 into his injured foot and on in to phase 2), and I'm at what Melania considers(in her warning text at the campfire) the point of no return. I collected both pieces for the 2nd great lift and took the secret area to grab the 2x Somber Dragon Smithing Stones from the pickup/quests there.
I had no idea there was a sewer area below the capital, I mostly just ran the roofs to the final boss and 1 shot him with Azurs(works great on him) but that freakin fire giant is almost immune to sorceries, I had to full-on melee that guy, and it was real, real close but I got him after about 10 attempts. He gave me 3 levels. I think I'm 90 hours in, maybe level 110 or so. I'm getting near the pinnacle of my power now. I can feel it. I also beat another guy who was pretty hard for me until I got +10 weapons, the evergoal that houses Black Knife Tiche at the end of Ranni's questline. So, so tough for me, but turned into cheese once I got that +10 Moonveil!
Anyway, 999999999999999999999999999/10
For anyone still using the glintstone style spells, imho, the best one is Glintstone Icecrag. In general I run:
Glintstone Icecrag
Carian Slicer
Loretta's Greatbow
Azur's Comet
Terra Magica
This covers ranged, the 1 shot trick, long distance shots, workhorse spell, and melee is for the Moonveil. The true purpose of Carian Slicer isn't melee, but rather an efficient if high risk way to turn mana into damage at a great exchange rate. It also serves as a great tool for confined melee since it cannot trike walls and I guess ignores enemy poise(or at least, isn't affected by practical enemy defenses, though I'm sure is reduced by their resistances).
One more thing, just in case anyone else missed it, when you go to Caelid via the exit of the cave with the stars underground, you will have to run down a long outdoor valley with giants shooing arrows at you. Once you get to the end, there is a HUGE pot, a building, and probably some blood stains. You can talk to the pot! You just have to be standing at the right spot. If you talk to the pot, he will show you 3 summon signs. If you beat all 3 without dying or using the campfire, you get a great talisman for your trouble that is very universal.