How does brace really works against this if you spend other defense token like redirect?

If you only spend brace, it works normally.

If you spend other defense tokens as well, brace only reduces the damage taken by up to 1 point. So instead of:

1 -> 1

2 -> 1

3 -> 2

4 -> 2

5 -> 3

6 -> 3

you get:

1 -> 1

2 -> 1

3 -> 2

4 -> 3

5 -> 4

6 -> 5

...and so on.

The timing and effect of other tokens is unchanged.

EDIT: Look ma, no quotes!

I had a play with HTT over the weekend and it really only provides a benefit (as shown above) if you are consistantly dealing above 4-5 damage, which means I think its pretty useless on anything less than an ISD. Rest of the time you are best to take XI7's.

My doubt come from the "by 1". I interpreted as you said but I thought about just one damage situation and if it could remove this damage. Of course it doesn't have sense but the words of the card seems a bit open to me.

It doesn't say "the defender can reduce the total by 1", it says "the defender cannot reduce the total by more than 1". He can certainly still reduce it by 1 or less, if the damage quantity so dictates.

In other words, the card does not give the defender "permission" to reduce damage by 1. It only forbids him from reducing it by more than 1. If there are any other reasons why the damage reduction should be 0 (e.g. when total damage is 1), those still very much apply.