Solved

[LuaScripter]

Thanks to ninja it's solved!

 

[Fare]

normal talkaction, when 'on', you check for some item in ring slot, if its exist, you add manashield condition with -1 duration. Same if you're saying 'off'', check for a ring, if it's equipped, removing conditions. There are available lua functions for all needed functionality, no clues what you wonder about.