Mindgames (https://www.wowhead.com/spell=323673/mindgames) is the Priest covenant class ability from Venthyr. Discussions with Publik about this, and playing with it while leveling, have led to an inconclusive outcome on how it actually works. What it doesn't do is wait until the very end to give Insanity. Whether it gives Insanity based on %s left on the debuff's value or at some tickrate (1sec?) and whether it gives discrete whole amounts or fractional Insanity is still TBD.

Until I can have a Shadow Priest that is Venthyr, support for this will be limited.

It is modified by the following Anima Power abilities in Torghast:

Earworm (https://www.wowhead.com/spell=342412/earworm) -- do these return Insanity? What's the duration when this occurs? Shield size?

Mindmancer Gloves (https://www.wowhead.com/spell=342411/mindmancer-handgloves) -- do these increase the total amount of Insanity potentially generated by 20% as well?

Tested this today. Returns Insanity instantly, no delay or pooling. Not worth tracking as trying to guess how much you'd be getting from incoming attacks is...difficult, to put it kindly.