Tension is the mood of the characters. You might have noticed that when a battle goes well, you'll have the character portraits yelling with a flaming background. That's high Tension. If they're sulking with a blue background, it's low Tension, and you should run your playable character over next to them and cheer them up. (Yes, really.)
You gain Tension by hitting the enemy, doing criticals (more if you hit the "That was AWESOME!" QTE) , and so on. You lose it by missing the enemy (unless you hit the "You'll get it next time!" QTE), taking damage, and being affected by enemy auras. Getting KO'd will drain a lot of Tension, too, so remember to give the character you revive a pat on the back before running off, they appreciate it.
What it does? It's basically a minor buff or debuff to more or less everything. More Agility, more damage, and so on. This also means that low Tension is a cascading failure, by the way. Low Agility means hitting less, means drop in Tension. On the other hand, as long as you stay alive, it's easy enough to stay at flaming rage tension as you just keep pummeling the enemy when you hit that.
You gain Tension by hitting the enemy, doing criticals (more if you hit the "That was AWESOME!" QTE) , and so on. You lose it by missing the enemy (unless you hit the "You'll get it next time!" QTE), taking damage, and being affected by enemy auras. Getting KO'd will drain a lot of Tension, too, so remember to give the character you revive a pat on the back before running off, they appreciate it.
What it does? It's basically a minor buff or debuff to more or less everything. More Agility, more damage, and so on. This also means that low Tension is a cascading failure, by the way. Low Agility means hitting less, means drop in Tension. On the other hand, as long as you stay alive, it's easy enough to stay at flaming rage tension as you just keep pummeling the enemy when you hit that.