Double-Click on the Spoiler a couple times <img src="/ubbthreads/images/graemlins/smile.gif" alt="" />
<span class='standouttext'>Spoiler : </span><span class='spoiler'> Are you sure Samuel was level 38? For me he was level 41. OK, I took him down in less than 5 minutes. The key was to ignore his minions and just concentrate on him (you can kill the minions after he dies. You could kill the minions first, but it is really a waste of time and potions. I also figured more would come anyways). Make sure your crystal bag is full and have a Large Shadow one in there). You will need a lot of healing potions (I used 84, mostly small ones though). Use your stat increase potions 2 or 3 times during the game as well, and be very quick on the pause key. If you try to run out of the room to have some space to fight him he will just unleash a barrage of all kinds of spells on you (he did for me so I ran back in and whacked him).
Now if you think that you are going to run out, or very low, on potions you have a MAJOR problem... you cannot get any more, you cannot go to the BattleField (at least I kept getting the stuck in BattleField bug), and you will need probably 100 - 200 larger healing potions in the next battle.
Good Luck <span class='standouttext'>Spoiler : </span><span class='spoiler'> </span></span>