If your on mobile and want to get easy levels, get an explorer note and a crossbow with a grapple, if you grapple on to the giga it cant hit you and u can kill it if you have a decent sword, aim the grapple at the hind hips of the giga, i killed one with hard brutal and it was level 365, took a few minutes and i got 4 levels which is a lot for the difficulty i was on and i was on level 53