We've had a few weeks to begin processing all that happened the Once Upon A Time Season 4 finale, now — how's everyone holding up? In case you need a small refresher, allow me to jog your memory: Gold is now powerless and in some kind of magical coma after he was saved from having his heart go entirely black. Zelena is pregnant with Robin's baby after tricking him into sleeping with her by posing as his actually dead wife, Marian. Emma is now the Dark One after sacrificing her soul to preserve Regina's happiness. Oh yeah, and Henry's the new Author.
That last point is a particularly interesting one, and one that hasn't been getting as much attention as it should do, given the whole "Emma's gone dark" situation, but let's discuss. Henry became the Author after hopping into the Heroes & Villains book in "Operation Mongoose - Part 1", taking the position from the awful Isaac, who threw everyone into an alternate storyline in which all roles were reversed. Once Henry felt the power surge through him upon picking up the pen, he immediately used the dying hero Regina's blood to zap them all back to Storybrooke. He later broke the pen in half once all was returned to normal, obviously scared of the responsibility and the power that came with it — not that I blame him.
But clearly the powers that be didn't write Henry as the new Author for the purpose of that one episode, only to abandon the entire thing in Season 5. Sure, it served its purpose in allowing him to momentarily play the hero and eventually write them all out of Isaac's nightmare of a story (thanks to the help of his moms, of course), but Henry has the heart of the Truest Believer. Just as he believed that Emma would eventually embrace her role as the Savior, and just as he believed that the Evil Queen could be redeemed, he's not likely to change anytime soon. His role as a constant beacon of hope in Storybrooke will translate well to his new position as the Author and certainly he was a good choice for it.
Of course, love can make you do things you may not have ever expected to be capable of, especially when the people you care about most are in danger. It's safe to say that's most definitely the case, now that Emma has allowed the Darkness to tether itself to her and taken on the Dark One role. While Emma has always been the Savior, she's now in the position of needing to be saved, and while Regina's the only one with the magical skills to even begin to work towards fixing it, Henry's the one with the ultimate power. Of course, all magic indeed comes at a price, and writing a story in which Emma is saved would likely compromise many other things in the universe, and the Author's code states that you're not allowed to write your own happy ending. Having Emma back is obviously a large part of Henry's, but he's also not a selfish kid, so the likeliness of his abusing that power in order to restore Emma to her former self is unlikely.
But it's not impossible. After all, Henry has basically been working for years not only to get Regina to transform from the Evil Queen to... I don't know, just the Queen, without all the murderous rampaging behind it. Thankfully, due to Emma's dedication to the same cause, that finally has started to happen. But Henry's also been desperate for some kind of stability in his life, and it seemed like he was just starting to get it before Emma was ripped away. Knowing all that he knows now — that Emma is the Savior who has sacrificed herself on numerous occasions for the residents of Storybrooke, for him, for Regina — the urge to do what he actually can to fix things might become too much to handle, and we might be seeing Henry put pen to page by the end of Season 5, I'd say.
Regardless of what Henry does with his Author powers, for some reason, I just can't see him messing anything up too badly. After all, if anyone knows the reality of consequences of bad choices, it's him. And while he'd do anything to keep Regina and Emma safe, I'm not quite sure that extends to sacrificing everyone else in the process. That's not what a hero would do — and he's the son of two of them.