The Quest for Karla - DS3

 Yes, that's a John Le Carré reference.

On my Pyromancer playthrough of Dark Souls 3 (altoholism is a great way to avoid dealing with the fact that you're stuck on some very tough late-game bosses) I dutifully held off on giving the Londor or Deep Braille Divine Tomes to Irina, allowing her to focus only on light miracles, and just held onto those tomes until I rescued Karla from Irithyll Dungeon.

They make you wait until you're pretty far into the game to do this, but once you get her, there are four tomes you can give to her - while you can give the dark divine tomes to Irina, buying any of the dark miracles will cause Eygon to take her away from Firelink Shrine and require you to kill him to get her back. And then, the Grave Warden and Quelana Pyromancy Tomes can only be given to her, as Cornyx will object on principle to the first one and then by tradition (he can't teach them because he's a man) for the latter.

Ironically, this means that Karla, who is a Sorcerer, only gets non-sorcery tomes. I actually had Logan's Scroll in my inventory when I talked to her, but you can only give this one to Orbeck.

Anyway, as a Pyromancer, getting access to Black Flame Orb, which is a dark version of Fire Orb, oddly enough. The timing is actually very welcome, as the headless gargoyles and the flame-keepers in the Profaned Capital seem to resist fire, so tossing this thing at them is more effective - though it does cost a bit more FP.

I've also infused a chaos gem into a longsword, so I now carry a Chaos Longsword and a Raw Longsword. Chaos infusion gives the weapon fire damage that scales with your Intelligence and Faith, so this is my go-to weapon for normal enemies. However, I have the Raw one for boss fights, where I'll use something like Carthus Flame Arc or other weapon-buffing spells, as I believe the physical damage is not decreased at all from those spells, so my damage should be maximized while the buff is up.

I am now more or less at both Yhorm and Aldritch - I tend to prefer going with Yhorm first. (I actually still need to kill the abyss monster in Anor Londo and open the big door, but that's a pretty quick sequence of events). I think my plan on Aldritch is to use the buffed weapon rather than hurling pyromancies from afar. When I fought him on my Sorcerer, this technique did work, but I had to spend a lot of time dodging his massive soul spear-like attack. His melee attacks are a little easier to dodge, and if I can keep him from doing his arrow spam, that'll be ideal.

EDIT:

I wound up taking down Aldrich instead with Great Chaos Flame Orb, which works very well on bosses that aren't super mobile. It hits for a pretty decent amount initially, and then leaves a puddle of lava that does even more damage after a second or so. This became by go-to spell for Aldrich and then the Dancer of the Boreal Valley - sadly, I got Dancer down to something like 3% or so on my first attempt and then failed to get out of the way of one of her attacks, so it wound up taking two more tries. Still, while she can move quickly when on the offensive, she's often slow enough that you can get both ticks of the spell off.

I've now gone through the Dragon Barracks and am on Dragonslayer Armor. I think Dragon Barracks might be my favorite "level" in the game - I think the first time I did it I really thought you needed to time your way past the dragons, but this is one of those classic FromSoft zones that seems expansive and labyrinthine, but by the time you open up all the shortcuts, it's shockingly linear.

I realized that the Mimic chest I left in Irithyll Dungeon actually has the Dark Clutch Ring, which could be useful as I start using more Dark Pyromancies and other spells. There are definitely a few things I want to go back for, but it's nice to make a lot of forward progress.