When is a discipline considered to have been used?

When is a discipline considered to have been used?

When is it played?
When does the effect take place?
In both cases?

To make it clearer.

If an action is played with discipline X and then a vampire takes the place of another with the mask of a thousand faces, who is considered to have played discipline X?
The vampire who played the card?
The vampire who carried out the effect?
Both?


Name: Mask of a Thousand Faces
[Jyhad:U, VTES:U, CE:U, KMW:PB2, LotN:PA, KoT:U, HttB:PSam2]
Cardtype: Action Modifier
Discipline: Obfuscate
[obf] Only usable by a ready, unlocked vampire other than the acting minion who is capable of performing the action. Not usable if any action modifiers or other effects have been used that could not have been used if this vampire were the acting vampire. Unlock the acting minion and lock this vampire instead. The action continues with this vampire as the acting minion.
[OBF] As above, with +1 stealth.
Artist: Jeff Menges; Leif Jones

The vampire playing the action modifier at the time the action modifier was played is the one considered using it taht.

If you check vdb, this is the rulling that would support that


The masking vampire can play a modifier already played by the masked minion. He cannot use a limited effect (ie. bleed enhancer) if a limited effect has already been used on the action. [ANK 20190117-1]

check also this thread. www.vekn.net/forum/rules-questions/77308-mask-of-a-1000-faces-and-bleed-modifiers#92987

I was thinking about actions, not about modifiers.

Imagine this scenario

2 vampires with animalism, obfuscate and presence. Both with a dabbler.

Vampire A plays Breaking the bonds
Vampire B Plays Mask of a Thousand Faces

Who can use his Dabbler.

Dabbler says:

Name: Dabbler
[HttB:R/B1, NB2:PMi2]
Cardtype: Master
Archetype. Trifle.
Put this card on a vampire you control. Once each turn, after an action (successful or not) is resolved during which this vampire used 3 or more Disciplines to play cards, this vampire can either burn 1 blood to unlock or gain 1 blood. A vampire can have only one archetype.
Artist: Matt Smith

Depending on the definition of used (played or performed) will define which vampire could use Dabbler in that scenario.

This afternoon I am going to play a deck with this issue. I hope I get an answer before.
If not...
I will judge that Use=Play (although it would be probably better to my deck Use=Perform and this way I will end with both vampires unlocked. If Use=Play you can only gain 1 blood. The vampire is already unlocked)

Editing my answer as it was wrong