Yea WaffleDee is right, since if you haven't been working on your smithing and crafting then could be a great time to do so. Mainly a good way is to farm the heck out of iron and bronze ore (you can get both easily in town after you open the bridge to the mansion during the first arc) and wooly fur if you tamed some for your barn. Ore used for smithing and wolly for crafting can raise it up nicely and make you some nice bit of gold as well.
But also this game is much more based on equipment then level since was able to plow threw the first arc with a lvl 6 wind spell I got dropped, and now finally getting enough good supplies to get decent equipment. But still neglecting your lvling isnt wise either, but you can be quite OP with the right stuff. Also be sure to bring friends as well since they do help alot, even to only be used as meat shields.
"You're dead if you aim only for kids. Adults are only kids grown up, anyway." - Walt Disney
If you're having trouble at level 120 on easy, then you definitely are having problems unrelated to leveling. Even storebought gear should be enough for this place at your level. If you're using the overrated spear, that might have something to do with it.
Gamertag: Archlvt (I no longer have XBL Gold) 3DS FC: 4296 3610 2207
Thanks for all the response guys. Actually I made a mistake - I'm in Rune Prana not Leon Karnak. I didn't see the name before and thought it was just an extension. Are there any specific weapons I should be gunning for? I'm working on crafting skills now and eating bread everyday. It's far too open ended for me and I don't enjoy it much, so hope to get it over with soon.