I was really happy being all intelligence for a long time to be able to do the most damage & full healing while being squishy...dying a lot. I was always told to use a staff too for more damage especially at bosses. But I respec'd to enough strength in order to wear the reaper bear set like others suggested in order to do better in pvp....I noticed that it doesn't feel much different than being a full nuke mage!

I did some runs in Red Dragon Slayer with the strength set on & it made it much easier to survive with higher armor/dodge....I would have had so many less deaths had I had done this much sooner. I would advise you to do the same before going for this quest.