Help me fight Yeldin

[inquirer]

I am now playing this game and its one of the coolest game that I have played in my gaming life!
But now I am stuck at chapter 13 of the game : I am to choose whether to spare the life of the dark Elves after the arena fight and I refuse to kill them so Yeldin gets mad orders to kill Althea and the game proceeds. Then the portal opens and the team escapes followed by Yeldin and at that fight whenever I try to fight Yeldin the fight is just impossible! Is it even possible to kill Yeldin in this Boss fight?! It seems that his life never comes down; the moment it reaches about 120 it regenerates. Please do help me!
Note that I am playing in hard mode.

[fabulaparva]

A general tip that comes to mind... (How the details have to be worked out depends of course on which twin combo you are using and which skills you've chosen.)
Find out what is the HP level that triggers YEldin's heal. At Nightmare-difficulty, it's somewhere between 200 and 300 HP, so I'd assume for Hard it's around 220-250. Try not to hit the main Yeldin below this level unless you have several characters attacking*) without any of Yeldin's mirror image interrupting your attacks. Keep your eye on the turn roster and skill delay when you choose the skills you want to use. To further help to get the turn roster to look something like Yeldin A, *)Vaelis, Shea, Riley, Krimm, Yeldin B, Yeldin.... you can speed your team up with Jariel and also slow all the Yeldins down with him to help you get yourself in a position where you can get your soldiers in a row. This way you can hammer him down with consecutive attacks from your party members without him being able to heal in between.

Good luck!

[inquirer]

Thank you for your useful post...
Trying to play the battle as you suggested...

and after about 2 hours of trial...
It works! Thank you very much for your suggestion.

Am I correct if I say that this is a tough BOSS fight in the game, because subsequent BOSS fights seem to be easier (I haven't completed the full game but have had four additional BOSS fights)

[Troyen]

Spoiler:

It's the toughest required boss, in my opinion. There are several boss fights near the end of the game that are even more difficult, but most of them are "optional". (I'm not sure I count Deceit as "optional" despite what Jack says, but he's only a boss under certain conditions.)

[cheska]

I'm playing at Hard level (no nightmare for me I'm only playing Hard to unlock achievements) the first time I tried I got frustrated and so I restart the match and chose to eliminate all his mirrors first. Then the battle finishes much faster.