It Might be the Revelations of One Harry James Potter.
It's an old story, written in 2012 on FF.net
Another thing you need to know is that Voldemort is a creation of Albus Dumbledore. We did some research and found that Albus made a Horcrux.
When Harry goes through the Gringotts hereditary test, he finds out that Dumbledore placed a block on his core magic power. Ends up taking him to trial and Albus acts very manipulative. And from what I see, continues to behave in the usual manipulative!Dumbledore fashion.
Master of the source of magic:
The main focus of this story is him and Susan Bones being a power couple and Magic chooses them, but it's really Harry who has the power, Susan just gains the ability to birth as many babies as she wants...weird. Lily died but became the embodiment of Love Magic, so she can commune with Mother Magic.
You see the combination of my gift to you and yours to Susan has made Mother Magic rethink everything.....Magic respects you and knows you will do what needs to be done....Magic sees you and Susan as the best hope for rebuilding our world.
Harry told her all that he and Lily had talked about and what she had become. He told her that magic had chosen them to be the chosen ones to turn the magical world around.
How I found this: I googled
"dumbledore made a horcrux" site: fanfiction.net/s/ and got lucky that it was the second result.