I decided to replay the game before moving onto FSII since I never beat that. Figured I'd try something difficult. Before the final battle with Zure, you're supposed to lose to him once but I thought I'd try to beat this version too.
Leveled my party to 65 each. Each has Divine Armor, Circlet, Sharenian Shields and Final Weapons upgraded twice.
Slash Blast still 1-shots my team at 2k+ damage but Darkness does 1-1.2k which all of my party lives barely. One full rotation of 7 Dragon SR Spells does almost 50% of Zure's health.
My strategy was to spend 1 full rotation of SR skills, get hit by Darkness to up my SR back to 75%+ and then do a second rotation and hope the numbers roll well enough in both rotations to kill him. From there, the swords are easy.
What actually happened: 1 full rotation brings him to almost half. He does a regular attack and knocks out Royke. I Final Strike with Zeru, Pheonix Feather Royke with Serene and Tuna Soup to full heal the party with Antlan. He uses Darkness and my party all goes low. A second rotation of final weapon SRs was enough to take out Zure. From there it was easy.
![FSI - Killing Zure First Fight Zure110](https://i.servimg.com/u/f11/12/87/62/54/zure110.png)
![FSI - Killing Zure First Fight Zure210](https://i.servimg.com/u/f11/12/87/62/54/zure210.png)
![FSI - Killing Zure First Fight Zure310](https://i.servimg.com/u/f11/12/87/62/54/zure310.png)
![FSI - Killing Zure First Fight Zure410](https://i.servimg.com/u/f11/12/87/62/54/zure410.png)
![FSI - Killing Zure First Fight Zure510](https://i.servimg.com/u/f11/12/87/62/54/zure510.png)
As you can see in the end, the story doesn't progress unless you lose but you get exp and money at least. (Unlike Drena in FSII apparently. I actually didn't even remember or see my old post until I was just making this one.)
![FSI - Killing Zure First Fight Zure511](https://i.servimg.com/u/f11/12/87/62/54/zure511.png)
For proof that I beat the first Zure fight and not the second one you're supposed to beat. (Compare the HP, MP and SR to the screen where I beat him. See that I'm able to fight him again after.)
The actual fight after became a joke. Darkness did single digit damage to my party.
![FSI - Killing Zure First Fight Zure610](https://i.servimg.com/u/f11/12/87/62/54/zure610.png)