Yes you spend gold for it. 5 million gold for the first ascension. 10M the second. 15M the third. And so on. There are a total of 6 Ascensions. From magic to eternal ascension.
To level up fast, get as much EXP Gain % as possible. Specifically 6× Quest Mythstones. If you can manage legend exp gain to combine, that’s good also.
To best farm gold, get hirling, high item drops % and gold find % . First ascension I highly recommend is Dealer or Fortunate because of the gold to progress for next ascension.
Or if you got hirling, get hirling first ascension as dealer and the main character using fortunate ascension for best gold farming experience.
For best farming experience for Ascensions , do packsize maps between floor 101-200 maps. Any higher or lower and the exp gain possible from enemies decreases. Also put Mythic 3 if you can and do the floors in 5 minutes each or less.
Best gold farming experience also at packsize and floor 101-200 maps.