[Spell] Chain lightning to zero damage

[Dinan]

sry for my english

I don't know, it seems a simple problem
but i still can't figure it out

how to make chain lightning zero damage?
i tried to edit it on object editor by setting 0 to damage field. but still wont work

 

[Wietlol]

There are 2 damage fields...
When I set "Damare Per Target" to 0, the chain lightning does not deal any more damage.