How exactly are blood arts triggered?

[Daddy Kaneki]

Reading through the database entries and researching it online and nothing is being made apparent.

[Azba]

You mean unlocking them?
Basically all you need to do is perform the relevant actions in combat and it adds to an "experience bar" at the end of a mission. When this bar fills up, you unlock a new blood art.
If you haven't got this yet, you need to get further into the story.

For example, anything listed under "X action" gains experience when you attack with the X button in combat. Aerial attacks gain experience through performing aerial attacks etc.
There's a little icon that pops up on the bottom left of the screen whenever you've performed an action that gains blood art experience.

If you mean using the actual blood arts in combat, they should all trigger automatically when you're performing an attack using the relevant button inputs as listed on the blood arts page.
So ones that "enhance fourth X attack" make the fourth hit in the X combo act differently than usual, etc.

All weapons have unique skills that also have associated blood arts, so to level those ones up you'd have to perform that unique skill in combat - e.g. with a Long Blade pressing R1 + Square puts you into "Zero Stance" which is required for some of the blood arts.

You do not need to have a relevant blood art equipped to level the others - they all gain experience if you perform their actions in combat regardless of whether you have a relevant blood art equipped.

[Daddy Kaneki]

Oh I see. So a "blood art" is in fact not a "special attack" as the game was trying to imply it is, but instead it just buffs your regular attacks.

Alright that makes sense; thank you.

[Azba]

Originally posted by ~A ℭ ℭ ℰ ℒ~:

Oh I see. So a "blood art" is in fact not a "special attack" as the game was trying to imply it is, but instead it just buffs your regular attacks.

Alright that makes sense; thank you.

Yeah more or less for most of them.
Some of them just passively add something extra to regular attacks, whereas others completely change the action that the usual input would perform.

A good example is the impulse edge long blade blood art.
By default, hitting R1 + X and then R1 + X will cause you to fire a short blast from the gun while in sword form.
The blood arts for Impulse Edge can change this from a short blast to a laser, rapidfire chaingun or a big explosion, all using the same button combination.

[BuffySlayer]

its depend on Blood Arts you select. for example Variant Scythe . if i pick ' Executioner Chop' continue press X it will perform jumps high to swing down at the 5th attack

if i pick 'Turbulece ' continue pressing X it will spinning Scythe attack repeatedly . so both Blood Arts are totally different but the same pressing X type

ps. this is Xbox controller

[AngryMexicanDog]

There are 3 levels of experience gain.
Lvl 1: spam that button (at some point it wont give you a lot of experience)
Lvl 2: Hit criticals (I think you need to hit the weakest area and see the WHITE effect)
Lvl 3: 3 consecutive critical hits