Quivering Blade - help needed

hi
(i'm german so plz excuse my bad english ^^)

i tried to capture the elite skill mentioned above from "Sun the Quivering" in the east of the wajjung bazaar but because of the quests i already did the am-fah in this area were green (friendly) and the bossmob didn't appear
i heard that you can make the am-fah enemies again by refusie drinking from the cup of brother tosai but i already completed this quest ...
so i was searching for a pug with players in it that are still enemies of the am-fah but desperately the am-fah stayed green as long as i was in that group T_T
it seems that i am unable to cap this skill from sun so plz help finding a solution for this problem ...
btw. i already finished shiro so if anyone can tell me another boss who has this skill ...
and yeah this is the only boss that is mentioned on xennon.com

plz help me getting out of that hell

ok, right outside of nahpui quater, is a guy named Brother Tosai, he'll offer you a Drink from the Chalice of Corruption, complete his quest, and he'll tell you the Amfah will be for ever your enemy.

Please read wiki carefully, you need to talk to bujo to get the quest of finding Brother Tosai, hope that helps

thx for your answer but i know that
i already drank from the chalice as i wrote above ... but i guess i have to complete the quest from brother tosai after this one also ?
well i'll try that ...

€: now that i cleared the second quest of brother tosai and another one just around the corner (couldn't remember the name atm but it remembered me of westside-story-like gang fights...) the am-fah turned enemies again so i was able to fin sun ^^ ... and of course cap the elite
thx again