The Dragon's Den doesn't screw around. It's an elaborate maze of unlocking doors and switches you have to stand on, which makes backtracking to save points rather tricky at times. Thankfully I'm emulating so I had a save state before the following:
GM: Upon returning to the formerly locked door, you encounter the red dragon! It roars and "Sacrifices its life force to make itself stronger." Roll initiative.
Cyan: I'll use bushido - wait I didn't mean to do that, hold on-
GM: Too late, Red Dragon's turn. It opens with Red Fang, putting Cyan at 0.
Cyan: What, no save?
GM: I'm not done. It follows with Red Fang, Celes you're down too.
Celes: What's happening, I was checking my spellbook
GM: It concludes with a Flare for... more HP than Mog has.
Mog: KUPO!
GM: Alright Locke, what do you do? As if I don't know.
Locke: Don't worry everyone, my build is perfect! By dual-wielding the Valiant Knife and Thief's Knife, along with the Master's Scroll, I will attack eight times-
All: WE KNOW JUST ROLL
.........
GM: Alright, so with those rolls... and accounting for the Valiant Knife's effect... congrats, you hit eight times for 0 damage.
GM: Red Dragon's turn, it attacks... ooh, you survived! Then it attacks again.
Locke: Yeah, that kills me-
GM: Don't interrupt. It attacks you again, and again, and again, and again, and again, and again. Eight total.
Locke: okay I'm sensing you don't like my build
I had fun with the names here. Locke's Garret from Thief, Cyan is Jetstream Sam from MGSR, Mog is basically a pokemon and also running an Impartisan build, and I'm the main character
TBH I kinda like finally seeing a proper puzzle-boss like in FF4 or FF5. 6 is great but the boss fights are pretty easy to roll over unless you're keeping your levels down on purpose.