Lamentation allows to apply rend 2 times , will 10% damage increase from rune apply twice as well ? so its 20% . wanna hear answer from some one expirienced or from some one from blizz )
This is so easy to test, I doubt you need anyone experienced to answer here. And I believe requesting an answer from Blizzard or the Mods is against forum censorship.
IIRC the 10% debuff will not stack from two of your own Rends but another Rend from another Barb would. Is only the Bleed dot that stacks for one Barb and two rends on the same target.
No. Ghost answered the rest.
In its current form, Rend is not worth using when pushing with WW. Speaking of WW, yikes, your build is in bad shape! Check out the complete guide: [Guide] Zodiac Rend (Season 20)
Give that a read, then re-farm or re-roll accordingly. If you have questions, ask in that thread!
No it does not add up the 10% dmg buff. Long time rend user. It is an additive buff anyways. not worth.
But blood lust is awesome for life regen