When Kunark came out, he was moved to level 62 or 63. If you attack him, you cannot run from him, since he is such a high level mob that he can summon you to him. He has a huge faction hit for being killed. And he hits real hard.
All of the main guildmasters are 60+ now that kunark is out, so they are all much harder. The faction hit from "warmly" will take you to "dubiously," however it depends on how high or low your faction at warmly is, since you can have different degrees of faction within a single con. If you intend to kill him, be prepared for a lot of work to increase faction. I have also been told that he does not always drop the headband, so it will likely require multiple kills which will ensure you become VERY kos, making it very difficult to increase faction. One option is to get him to really low health, and then have an enchanter memory wipe him, a cleric atone him, or a necro do screaming terror (I think that's the spell) on him so that it wipes his aggro list and you will not get faction. Somebody else that can finish the kill will have to be willing to help, though.
is there a serious faction hit to killing him if you con warmly. Also, how difficult is it to kill him? Will the other monks show up? Does he drop the headband everytime?