Let's add it up:

Perfect 270% Eth Rune Master (Zod, 4x 40/15 ias) would be at 524 max dmg with 60% ias. Ettin Axe is a base 10 Weapon, so you'd need 10 more IAS from somewhere to hit 4fpa Zeal with lvl 20 Fanat

Perfect 400% EBOTD Zerker hits 530 max dmg, has 60% ias, requires 32 less STR, adds +30 all stats, and the -25% target DEF. Base 0 weapon, so you need no IAS for the 4fpa Zeal.


I fail to see how the Rune Master beats the EBOTD. The -25% target def adds to be roughly the same (vs. a high def character) as another Angelic Ring (assuming ~lvl 90), and wearing the Raven Frost for CBF gives a good dex mod, and a moderate amount to AR.

That's my opinion on it.