Here is how the classes rank specifically for a solo playthrough. Note that this differs from a party tier list; classes that require support (like the Ranger) rank lower here.
The Necromancer is often argued as the "best" due to its sheer DPS. It has the fastest clear speed in the game if you don't get hit. inotia 4 best class solo
: Since you aren't splitting loot between party members, focus all your resources on your main weapon. Use the Fusion Machine to reach Chaos or Epic Chaos tiers for maximum attack power. Here is how the classes rank specifically for