Can you post your roster? Would be easier to make suggestions with complete information. :)

I am stuck on Nether Spider L70.  My roster is posted under the Unkillable CB link.  

Not trying to steal the thread.  Just need the same help.  

normal or hard?

how far are you from drexthar?

There are 2 strategies to beat Nether Spider:

• Kill the spiderlings - This essentially revolves around having enough DPS to kill the spiderlings each time they spawn.  Ideally you probably want to have a heal reduction on the boss at the same time
• Don't kill the spiderlings - This involves entirely ignoring the spiderlings.  They only heal the main spider if they counterattack (i.e. they get attacked first).  If they just attack normally then no heal takes place.

I find that the second strategy is the better one in the long term, especially as you start to progress up hard doom tower.  As a result, the second strategy is the one I want to focus on here

To survive the second strategy, you just need a really good sustain team.  This is a team with any AOE attacks turned off, and focused on healing and survivability.  An example of such a team for @ClosedPoly would be:

• Scyl - Passive healing and a lot of defense.  Also revive.  Turn off A2
• Scyl - Passive healing and a lot of defense.  Also revive. Turn off A2 
• Duchess - revive and brings a lot of damage reduction in terms of passive and veil.  Also brings group heal and a small shield
• Helicath - Block Damage.  Turn off A2
• Sanguinia - Full debuff cleanse, heal, and also hits like a truck.  Same affinity as Nether spider

The goal of this team is just to keep everyone healed and running.  At this stage it is just a matter of time before the Nether spider drops, as they slowly whittle away at the bosses HP.  Having a full cleanse champion is important, as you want to remove all of the poisons if they start to build up

Teams like this can be full auto teams, but as you progress more into harder doom tower stages then you might want to manual the fight to ensure that the block damage or full cleanse happens at the right times.

If you find that the team is surviving very well, then you could drop one of the Scyl's and bring in someone like Mountain King to deal a lot of single target damage to the boss and take it down faster.  He is also the positive affinity which helps

Echo the second strategy, and add my dth mvp vogoth :)

Normal.  

I beat Nether on L70.  It was slow and ugly.  7:25.  Duchess, Scyl, Heli, MK and Sanguina.  Several champs went down but Duchess/Scyl revived them.  Sanguina was fresh out of the vault.  No gear, books or masteries.  

I was trying to kill spiderlings before and I couldnt kill them all fast enough.  

Thanks for the help.  

What stats will Sanguinia need to be most effective.  I am grinding her for masteries now.  Does she need books?  Should she be 6-60?

Personally I think she'd function just fine at 50 and doesn't need masteries. I don't know if I'd want to book her, either. I have to imagine you have better places for your resources. 

What stats will she need?  

I always have someone grinding for masteries.  I can grind her and level her up at the same time.  I will save the books.   

Most important stats are HP/DEF/Speed. Accuracy if you want to try to land the debuff transfer.

Nice work.  

I agree with dthorne in that I wouldn't book Sanguina, and also keep her at 50.  For this particular purpose, she just needs to have her full cleanse ready on the 3rd round (the boss round) and use it as an opener, after which she has done her job.  If you are looking to full auto then just turn off her full cleanse in round 2 so she never uses it