Every character has a list of Artes and some are technical based and some are strike based. Is it possible to unlock all of these Artes by forcing your character to go back and forth from technical and strike or am I locked out of Double Demon Fang if I learn Fierce Demon Fang?
Double Demon Fang
Technical
To Unlock : Demon Fang used 50+ times
Fierce Demon Fang
Strike
To Unlock : Demon Fang used 50+ times
Best Answer
Without using glitches, no. It is not possible to obtain both T & S level 2 & 3 techs from the same move tree. Techs that seem obtainable because you are on the correct side of the T/S bar and have the prerequisites for unlocking them appear blue on the tech screen.
Using your example, you might see this case:
This is described as such in this big FAQ post, specifically looking at the How do I learn techs that are in blue? section. As Fambida mentioned in his comment, there is a 'Tech Glitch' that involves switching the user you are trying to glitch with out of the first party spot, and setting an arte shortcut for that user. This allows them to learn both S&T type, and adds some implications to how you can chain these artes together.