Judging by his level, his pretty much ended all quest available before the fight with laiken. The problem now lies here would be your skills, as well as gears. IF you had a screenshot or infos of your defense rating, then things will be clearer. Also by skills you mentioned invested, your character is just like jack of all trades, which major nothing in the end. If you are really a warrior guy, I dont think you will have so much points into other skills after investing in your major warrior skills.
This is my ranger defense rating before fighting laiken. And from my experience, the gear is capable to last me for another 5 to 6 level more at least. Also how you configure your necromantic creature? What head you are using and level of the head as well.
Joram: the most significance differences between high and other mode are, mobs deal more damage to your character. The hp also seems bit higher, which I cant confirm. Your attack also do bit less damage on them.