Ys 2 Chronicles+ Tyalmath (Nightmare difficulty)
0My suggestion for Tyalmath is to lure him to either the right or left, shoot fire once, then go as far to the other side of the screen, and repeat. The biggest issue in this battle (at least for me) is that his ice pillar thingies that he shoots are sometimes giving you very little room to breathe, especially if you are close to him. But the further away from him you are, the more space you'll have to maneuver. Hence my strategy of specifically luring him to one side of the screen and keeping distances.
During the battle, chunks of ice will appear on the battlefield as well. They are very hindering. I suggest destroying them if you can (unless they really are out of the way) to keep the battlefield safe from obstacles. I once got stuck on one and then his ice pillar things were shot and I couldn't move (or else I'd take damage from them), and then he jumped on me and I died. So destroy them.
In this video, I have the tier 3 sword and shield (which are the best that you can have at this point), but I still have only the tier 1 armor. Ideally, you should have either a Celceta Flower or three Herbs equipped to heal yourself, if you are taking a lot of damage.
Oh, and I had already visited the boss room and left, hence why he was already jumping at me right off the bat. My save was done after triggering the boss battle and leaving the room like that, so I couldn't exactly turn back. I have no clue whether this is better or not. It's more of an oversight on my part, actually. I realized "oh hey, that's right, I wanted to make a video of this" by the time I had already entered the room, left it, and saved. I don't think it's either a good or a bad thing. It probably makes no difference whatsoever, other than that the battle starts immediately.