Hello,

As long as the barriers stay, the person will receive a buff and whatever bonus the ninja gives to the players team (example Gaara providing shields per turn). However, once the barrier goes away you lose the buff, and the ninja will no longer provide any bonuses. Same applies as someone else using their barrier.

Barrier gives buffs whenever it is active, buff clearing cannot remove barrier bonus. Barrier buffs are lost immediately when the barrier disappears. Barrier buffs will return when you put up the barrier again; (the text that says +attack/+nin ect will be displayed only the first time you put up barrier, but the effect will still take place in subsequent barrier activations.)

and what happens if two people of the same team casted the same barrier? both remain buffed?

Only one barrier can be active at time- one which was casted later will remain and provide buffs.

Depends on the barrier. Most manual barrier only affect one's own team whereas passive barrier (like that of mei, onoki etc) affect all teams. Only 100% confirmed manual barrier that affect all team is hashirama, thou jirobo animation shows the buff animation for other team as well, I was unable to observe an actual damage difference.
No, the buff does not stack, so it's never 80% to all (40%x2), but rather 40% to 3 teams vs 40% to one team.

One thing to note, however, is that regardless of if the buff affect other teams, if the barrier comes with a passive ability (like Mei's poison, Yamato's extra attack), all of the same ninja will get to use the passive ability.

Yes, this means that if you have konoha traitor's orochi AND first hokage in each of the 3 teams, it can trigger 6 times per turn (3 hashi, 3 rez hashi from orochi)

This post was last edited by PraiseLuka at 2017-6-27 23:50

thanks PraiseLuka, that explains it all :) I was talking about Mei in a team with 3 water-based people
Just noticed that when 1 Mei casts the barrier, most of the team gets buffed. When the 2nd Mei casts it, just couple remaining chars are reflected as receiving a buff