@Winter G
the amount of experience required is pretty high. 1,843,200,000,000,000 or 1.8432 Quadrillion which is 1.2 billion demons if he kills 50 per second it will take 10 months to get to lvl 40. Provided demons give 1.5 million experience each and he attacks non stop, if he finds 15 million experience demons it'll take a month but if they give 150 million it will take 3 days.
so let's hope he finds that portal to the lower level and gets 150 million experience per demon. Tho he will only have 1 hour at the lower level. Also the mothman boss will probably give a good idea on how long it'll take based on experience it gives (hope it gives hundreds of millions experience