this is my [Kullervo] build, its meant for spamming 12X heavy attacks. [Sacrificial Steel] because [Blood Rush] doesnt double on heavy attacks, we only use [Focus Radon] since [Kullervo] naturally has 75 and efficiency caps at 90%, and it takes less space than [Focus Energy]. we also use [Focus Radon] rather than the other efficiency mods because it allows us to get another unique status effect on our melee that our primer doesnt have. normal [Organ Shatter] because [Kullervo] has heavy windup speed on his passive. melee exposure is there for acolytes, even without it this build will one shot them for a while, and [Dreamer's Wrath] for the crit damage.

ideally you would want a 25% toxin roll, for other builds outside of heavy attack setups, but anything around like 30% is fine.

the gameplay loop is simple, build combo to 12, swap to your primer, collective curse a cluster of enemies, prime them, cast wrathful advance. you dont necessarily need to build back up to 12 since you will be doing so much damage, but be sure not to drop too low.