IMPORTANT after a lot of testing and a lot of forma later i can confidently tell you that despite the base stats for the base [Pyrana] seeming more beneficial (ie. more fire rate and multishot) the passive that the prime variant has outpaces the base version ten fold therefore meaning my previous statement of this being better then prime was a blantant uninformed lie my apologies. This is the current build that I am running for plague star with my pyrana prime (https://overframe.gg/build/898421) I have ran plague star over 300 times so far and roughly 100 of those were with base [Pyrana] the rest with prime and again after testing its a shame i used the base version for so long

if you are really looking for optimizations the base pyrana provides more fire rate and more multishot but it has worse crit stats (barely) and slower reload // while on paper this would be correct it is not since the prime version has a passive trait which states "3 kills within 2 seconds of the previous kill summons a second [Pyrana Prime] for 6 seconds, doubling its magazine size and increasing its fire rate by 40% (pulled from the wiki) this alone already solves the fire rate. magazine and multishot problems that the [Pyrana] faces but add the additional decrease in reload time 2 additional rounds in the [Mag] (12 bonus with passive activated) makes the prime version eons better

the hemocyte wants as much multishot and crit damage as your can get also you mod for base heat damage since its 50% weak to it

in reality it doesnt really matter which type you use but technically base is better for plague star exclusively

if you have a riven go for MS - CD - Fire Rate - any decent negative