So long story short one of my buddies had toughness issues which I then pointed out that unlike me he didn’t use Warcry but then he replied to me with “but I need rend because all the top Barbs on leaderboards are taking it” which sparked a small debate.
So my question is why do people take Rend when it’s already being applied through Whirlwind? It just doesn’t seem to make any sense and none of us knew an answer to this.
This is addressed in the complete guide:
Rend is on the bar so you get the added benefit of the rune. Your buddy is wrong.
so it’s literally just that? nothing else? so in theory you can just swap this out correct?
You do NOT want to swap out Rend in solo play (or in most group scenarios). The rune effects are extremely important.
why’s that? It doesn’t seem to be that useful. Could you please explain?
The bloodbath rune applications of rend stack separately from ambos or manually applied rends can potentially double your damage output
so how? just passively it gives you double damage?
Enemies killed while bleeding cause all enemies within 10 yards to begin bleeding for 1100% weapon damage as Physical over 5 seconds.
Basically, when a mob dies with bloodbath rend on it, it puts a new rend on surrounding enemies that stacks with the rends that ambo’s puts on them. So instead of 2 stacks with lamentation alone, you get 4 rends, or double damage.
If your friend is having toughness issues, have them wear/cube a band of might and use Ground Stomp every 8 seconds.
It can be swapped out for T16 and low GR, but is mandatory for high speeds and pushing, use the Bloodbath rune.
okay that makes sense
For T16 is Bloodbath very good too. You WW through big pack. One (or more) mob dies -> all mob dies and you have not to stop.
So it’s only useful once enemies die? Kind of like the rampage passive? Right? or is it just permanent double damage
If you gather a large enough pack, once one enemy dies, if the rest are at low enough life, you can see a cascade effect as death-applied rends stream through the pack, killing everything, or close enough to it that you can move on. It’s hugely advantageous when you gather a bunch of elites and trash mobs close together in order to pop a seasonal effect on them.
It isn’t permanent double damage, but when applied in the correct situation there isn’t another skill/rune combo out there that will be better choice.
oh alrighty. Sounds good! just doesn’t help with the glaring issue that this build has and that is killing a rift guardian 
Easy tip: That’s why we use Bane of the Stricken.
Coupled with CoE, Ruthless and some +Physical damage any rift guardian will go down.
I don’t run Rend on my bar for T16 and everything gets one shot including elites, so at least for me, it’s not needed. I run Sprint in that slot instead.
Once decently geared you don’t need it on your bar for t16 it says this almost word for word in the stickied guide for ww at the top of the Barb forums.