As we know,it's important to upgrade you skills in game when characters become more developed.you have to keep using your attack skills if you want them to level up and high level ranked skills is what you want! Not only are higher skills stronger and faster but constantly using them and hitting the next rank levels up your stats, so if you Rank Up sword or magic skills and got to Double Master at level 60 you would easily be able to wear higher grade equipment than normal.Getting up your skills requires you to hunt enemies rather than doing quests.
Raising Magic Skill is exactly the same as raising Sword Skill, Upgrade skill however is slightly different. Upgrade skills only rank up when youve ranked up your Sword or Magic skills so if you had Master in Sword skill you would have Master in Upgrade - if you then got A.Master in magic you would then have A.Master in Upgrade. Always remember to purchase your Upgrade skills as they can make you character better and can add stuff like HP every time your skills hit a new rank.