Hello ,
I had some problems with the beholder too ...BUT i've found the way to beat him ..
His regular pattern is " easy " , it's right . At his 25% of life , his getting enrage and it's not good for you !!
So , like the two-head giant ,
first , you have to get him near 25% of his life , and KILL him in one break armure then .
Take Attack , Bersek potion before your last break armure ,
Recommended skill :
Assassin
Divine blessing
Give your maximum power in order to kill in one shot !
...And there is no way to reset your skill points unfortunately ....
I had to lvl up a new personnage too ...
You can "test" your skill , save and reset with the tips ( cf . page 15 , topic " arcuz 2" ) ,
good luck et sorry for my english ... :)