mantra question

[HardRock]

i have not yet seen a skill which does not trigger some kind of delay; even if its just <1 sec.

Neither of these skills have any kind of delay, so you can use them on the move or as fast as you can: Shouts, Caltrops, Smoke Screen, Shadow Power, Preparation, Blinding Flash, Breath of Heaven, Mantras, Horrify, Spirit Walk, Hex, Soul Harvest, Diamond Skin. I bet there are more skills like these, but they weren't available in the beta.

[WhiteGiant]

Neither of these skills have any kind of delay, so you can use them on the move or as fast as you can: Shouts, Caltrops, Smoke Screen, Shadow Power, Preparation, Blinding Flash, Breath of Heaven, Mantras, Horrify, Spirit Walk, Hex, Soul Harvest, Diamond Skin. I bet there are more skills like these, but they weren't available in the beta.

there is no cast animation which consumes time before the mantra / diamond skin etc. gets active but there sure is a delay until you can cast your next skill.

[Such Violent Storms]

there is no cast animation which consumes time before the mantra / diamond skin etc. gets active but there sure is a delay until you can cast your next skill.

There are some skills where that's also not true, I believe Diamond Skin is one. And, even if it is, it's in the realm of a tenth of a second. Which is completely irrelevant.

[Hadrial]

I have an unrelated mantra question that fits into this forum's topic.

Mantra of Retribution/Retaliation.
Increases the amount of damage reflected by the mantra to 60%.
Does this mean for 3 seconds afterwards you reflect 120%?

[Threepwood]

There is no delay when casting a mantra (at least as of the last beta patch where they were available). In fact you could even activate the mantra while attacking with a generator--mid animation. I believe blinding flash works the same way.

[The Rockman]

I have an unrelated mantra question that fits into this forum's topic.

Mantra of Retribution/Retaliation.
Increases the amount of damage reflected by the mantra to 60%.
Does this mean for 3 seconds afterwards you reflect 120%?

Here the bit of text that important "for 3 seconds after activation the effect is increased to 80%". So nope its boosted to 80% for 3 seconds regardless of what rune you have after this it drops to 40% unruned and 60% with Retaliation rune.