User blog comment:Caudyr/Abilities List From the Author + Translation of Abilities as I go Through the Story.../@comment-63.136.112.217-20150604182208/@comment-4784862-20150605011450

I don't think he loses them.

I'm pretty sure he  keeps  them, as he comments on when he tests them out with some Ogre Orbs shortly after getting the ability.

However, they obsolete...as in, they can't be used with what he's got since it's made using them.

I think "Synthesis" is actually just a combination of abilities using that ability that causes a better ability to be formed, but...it still makes use of those abilities when it's active.

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For example... 【 Recognition Difficulty 】  =  【 Presence Sensor 】  +  【 Recognition Obstruction 】  +  【 Sneaking 】

When  【 Recognition Difficulty 】 is activated, it likely activates  all three of the other abilities  on its own, so that they can't be "stacked" with each other.

It likely continues to activate these abilities even if he synthesizes one or more synthesized ability with others, like is done with  【 Roar of the Black Demon 】, which was synthesized with  【 Roar of the Black Ogre 】.

【 Roar of the Black Demon 】 will activate the ability that was synthesized with  【 Roar of the Black Ogre 】 to create it  AS WELL AS  all the abilities that were synthesized to create  【 Roar of the Black Ogre 】.

That's the only way I can figure for him to say they're "Obsolete" when it's clearly said that they aren't destroyed when he synthesizes them, anyway.