Haunting Guise does not increase all damage dealt. Only some of it.

After some testing, I see that Haunting Guise increases all damage dealt on for example Ahri's Q, both the magic damage portion and the true damage portion.

What I've found so far - It does not increase:

Ignite damage - Even tho ignite activates the item and builds up stacks Conqueror Keystone - The physical damage of a champion's basic attack increases, but not the true damage(Which should be a portion of the clean output). With this, I wonder which other sources it does not buff. - - -

It seems I can't do TABs in this editor, making my post ugly.. Sorry.