DoA question

In the Domain of Anguish....how does the Necromancer die instantly (not the pet trick thing) before the tank agro's the mobs....and why?

That necro sacrifice himself til he die, when he die so many times**. He will have max dp which make his hp=1* and when that happen, everytime he use energy regen skills such as bp. He won't lost anymore health and that enable him to spam bp as much as the team need.

*You will need a certain combination of armor runes and off hand.
** If that necro have a certain amount of heath and then die just 1 time (-15% dp), he will have hp=1 right away.

[skill]Blood is Power[/skill]
note the 33% health sacrifice

3x use = dead

at 1 health, 33% of 1 is .33 rounded to the nearest whole number means no sac. The game mechanics make it so at 1 health the necro doesnt sacrifice to use the skill, but... one parasitic bond and you're toast ;P

How is hp1 acheived?

You cheaters are something.

How is using a skill as intended cheating?

It's not cheating, it's just using a 'feature' of the game, slightly differently than it was intended. ANet has no problem with this sort of strategy, otherwise, 55 monks would have been removed from play years ago.

As said, it's not cheating, it's just a smart usage of the game mechanics. If anet didn't want this to happen , they would have rounded up .33 health to 1 instead of 0 a long time ago.

As for how the one HP is achieved, in detail, add 5 superior runes to your armor, two of those runes will be identical and the attribute bonus won't stack. The -75 health will stack though. This will effectively lower your health from 480 - (5x75) = 105HP. Then use the -50HP cesta that you get as a reward from the cities of ascalon quest and you will have lowered your health to 55HP. Once you die, you will get 15% DP that will be calculated from your max health at level 20 and not your actual health. You then end up with 1HP and you can sacrifice as much as you want.