@Blizz Ultimately this isn't my decision. I was just explaining what could lead to what. The important factors are how well one can use their abilities or the abilities themselves. I mean take a look at Dimitri for example: The only reason I stated IC that he managed to squeak by with a hero ranking during his first year is the fact that his powers play an obvious offensive and defensive role despite his pacifistic nature and general inexperience using his abilities at the time.
With Jack there are indeed limits, just not immediately apparent ones. For example his drawings are limited by imagination, which although theoretically limitless, will not always guarantee a solution to a problem immediately. Adding to that, it's pretty hard to create something while in combat, simply because the brain would be forced to multitask between figuring out the most appropriate tool for the job AND keep up with the fight enough to avoid injury. Then you'd have to take into account that ink can be diluted, evaporated, or even burned away. So people like Ptolemy and Xiu Yong would be very high risk individuals for Jack to fight. Lastly, and most importantly there's Jack himself, or rather his body. I'd like to assume that none of the people thus far are capable of using their powers or fighting indefinitely, simply because of the fact that the body can only do but so much before it gives out. From what i've seen, just about everyone here can be put down in some sort of way that would be considered normal: fatigue, blood loss, gunshots, stabbing, bludgeoning, suffocation, drowning, burning, electrocution, at least one of these things can be considered a very real threat to any individual character.