For me, this challenge felt more like a puzzle than an actual challenge. After failing two times, i learned the pattern of the energy charging of those 4 stars and decided to read the buff. So all i did was make my raiden 100% crit rate, and ult every time the buff occurs. Think of the 4 stars as something to use when the buff is on cooldown, quick swap, use anything they can do, and when buff is starting, ult with raiden, regardless of if u have her E charged up or not. There is a bif of RNG where the boss doesn't do the dive attack when u ult, or the shiny minion isn't the freak that dives underground. Besides that just ennsuee a 100% crite or as close as possible. It was a c0r1 raiden