Yeah, he's on the top level of the Flying Fortress (or "Sky Castle" if you're an old-school purist). I intentionally spent a good half hour wandering around up there just to see how bad he was. I think I made it three rounds.

Actually, now that I think about it, I know of a worse enemy type than the Warmech. Although, they're only really fierce in groups of three or four. There is a certain type of enemy in FF2 (the actual FF2, not FF4) that you encounter frequently in Pandaemonium (the final dungeon) called a Death Rider. Those things have three distinct qualities that make them unbearable to fight.

1) Their attack stat is enormous.

2) Their standard attacks cut right through any armor you're wearing. You could have full Genji-wear on your most resilient character, and it won't blunt the damage one iota.

3) Their standard attack has a life-drain trait attached to it.

So, these Death Riders will attack a character, do about 1,500-2,000 damage each time they hit, and they get about 90% of that back in drained HP. These guys are regularly encountered enemies in Pandaemonium, not bosses, not mini-bosses.

The only flaw they have is that they rarely get the initiative in a battle. But, all that amounts to is that you frequently get pre-emptive attacks in the first round. If you're fighting two, and you get a pre-emptive, they're no problem. If you're fighting four, and you get a pre-emptive, you'll suffer. If you fight two even-keel, you'll suffer. If you fight two and they get the initiative, good friggin' luck. If you fight four, and they get the initiative, you're dead. That's all there is to it.