Holy crap, I actually beat him! I'm better than I thought! lol.
Ok, so MAYBE I'm a little higher level than expected, and MAYBE I did some save state abuse, but no where near as much as I thought would be required. I just had to make sure my pegasus knight didn't get hit twice and die, and that was the only abuse I did. I lured the Dozer/Tozeh boss out by moving my Cleive into his range, and he moved to attack me. I then warped Force behind him so he couldn't retreat to heal. It was then just a matter of barraging him with spells and arrows until he fell. Slayder only attacked once, and spent the rest of the battle sitting still as no one was in his range. It took a dozen or two turns to do so with my characters only doing 1 or 2 damage a round, but I got lucky with some crits and was able to do a whopping 4 damage instead with spells like excalibur. That was a nail biter, seeing if it would crit or not, but I got lucky. Not something I suggest doing for everyone, but man, I am SO glad I was able to beat him without anyone dying. If the pegasus knight would have dodged that last blow 'normally' I wouldn't have even needed the save state abuse.
Now the only question is... does the retreating general (slayder in my patch) actually ever show up again as he promises? Hehe. I hope so, so I can kick his butt too :)