the evis part is only really important there, but the rubi in general is a very good item. any damage that you deal while it is equipped heals you for %12 of damage dealt
this is useful for anyone
slag is important for zer0 to maximize melee damage by slagging them 1st.
the gun isnt about pure damage. it is relatively weak in that department. its useful for its healing. i like slag because for me it gives more utility for 1 item slot. it serves as health regen and slagging. --- Crazy? Crazy with low prices on Wind Brahmin. You buy one!!