Hel will become Harry’s patron god.
While Hel has explicitly told Gabriel/Loki that Death has a claim on Harry that prevents Loki claiming Harry as one of his own, it’s probably a
Foregone Conclusion that Hermione’s closest friends will learn more about her worship sooner or later. Since Gabriel has never been able to turn Hermione down so far, he probably won’t actually reject Harry’s offer of worship when it comes, but instead compromise by arranging for Hel to appear to Harry on his behalf, allowing her to represent her father and her master’s investment in Harry.
Gabriel will be able to heal Neville's parents.
Just as Castiel was able to heal Sam's madness in "
The Born-Again Identity", Gabriel will be able to save the Longbottoms by taking their madness away (as above, operating on the premise that Hermione will inevitably include her Hogwarts friends in her worship). Of course, given his nature, Gabriel may pass their madness on to someone
else rather than keep it in his own mind, which raises a few interesting possibilities...
Gabriel/Loki and Hecate will come into open conflict at some point
With Loki taking an active role in the wizarding world through Hermione (to say nothing of the possibilities of Eve's interest being aroused by Fleur's worship of Loki), Hecate may attempt to re-establish her authority as the origin of the wizarding world, which would mean opposing Loki as the oldest and most powerful pagan god involved in society at present.
- It's possible that in order to do this, Hecate will revoke the blessing she gave to the Wizarding World's family lines and only return their magic if they agree to worship her again. While the ones who refuse are left magic-less or killed, or turn to Loki for his Blessing like Hermione has and join his side in the 'Pagan War'.
