ok, since i've seen many failures of tanks, i've searched how to avoid it, and the main reason those tanks fails is not the problem of the tank himself with his aggro but the party he is with. there is effectivelly some skills that render the target immune to p.mez and m.mez wich render the target immune to "taunts" (that are now more a skill that force the target to attack the tank for a certain amount of time). and there is skills that makes the target change or lose his current target. people usually must learn by themselves how and when to use those skills, but it seems they just pay attention to the number it show over the monsters head ... i will list there the skills that people should not use in instances untill they get used with them in non risky area. othell rogue : tyrr warrior : yul archer : wynn sumoner : feoh wizard : agro stack mechanics or agro reactive mechanics ? l2 was before on an agro stack mechanics. meaning each damage or each heal point was converted into a number and accounted on every people who have engaged (or being engaged) by the monster, stacking. the tanks class was given agro taunt that was not counting for damage but augmented the number of agro stack they got of a certain valor. now, l2 is based on an agro reactive mechanics, wich introduce not alone an agro scoring but also some mechanics of targets like in aion. the first who engage a monster or get engaged by a monster will get a multiplicator of certain amount for his agro score. every targeting cc, untargeting mechanics, or cc based on m.mez or p.mez generate agro toward the monsters, modifiate by a certain amount depending on landing chance/skill level, and if the player is the first or not to engage the monster. taunts do not more have aggro score but now work on the following model : tank.agro=max.agro.register.on.mob+random amount depending on the level of the taunt. the level of the taunt also determine if the taunt lands, depending on the monster level (or not). proper use of progressive heal : progressive heal, heals your target for x amount depending of the number of ally around it (up to 10) and 40% hp to the other allies. problem is the following : if there is numerous ally around the tank (ie heavily close range party + lots of cougars), and you land your progressive heal on the tank, the tank will be healed for a small amount of heal and the pt member around will be healed for 40% of their hp. solution and work around : put the sustain on the tank, and the fairy on the iss (who need to be always in close range) and do progressive heal on the iss, this way your iss should be fine (he takes ae from monsters from time to time) and you tank will always be healed for 40% of it's hp. if your iss run away, the other solution is to put the couple fairy/progressive heal on a close range (tyr or othell or even a cougar).