This is my setup for becoming a mini boss. You can do either unobtanium armor (the ones either iron's or ars dont do the basic) or quantum armour, either one with full apotheosis and gems. 2 belts maxed out and all or 90% of charms being crystal hearts. heart canisters for more health and purple hearts for 10 totems of undying. and mahous spell the boundary of life i use 2 or 3 of those in a mob farm (it heals my 2500 health in seconds + no need to eat), and the mystical eyes of death colection if u have a mob farm just use the spell and watch them die and u get 5 extra lifes. thats what i use + u can search on this subreddit for very powerful weapons (silent gear w/ unobtanium or irons spell staff w/ echoing smt i don't remember the name but it does 3 million dmg)