Ok after some recent updates on the server we have to fight both twins at the same time so a change of tactics is required.Imo the way we should fight them is like this:
Group setup:20+ ppl
Agro:Both twins attack.The main tank agroes Grand Warlock Alythess(the fire spell casting twin).Off-tank takes Lady Sacrolash (shadow spell casting twin).
Notice!!! Both twins are on enrage timer of 5 minutes!!!
The main tank+all the dps focuses on Grand Warlock Alythess.She must be taken down for max 3 minutes so maximum dps on her is a must.
When she starts to cast spells the group must use all tools (like Shield Bash,Kick,Earth Shock and other spell interrupting skills) to disrupt it.If this is done properly required healing will be downed to a minimum and the chance of wipe also.
After Grand Warlock Alythess is down all ppl focus on Lady Sacrolash which during that time has being kept busy by the off-tank.Maximum dps is a must again as she has to be taken down for max 3 minutes because of the enrage(2 if the off tank doesn`t have
Flask of Petrification ).