I can say this without a doubt that the relationship between Gray and Juvia holds a special place in the hearts of many including my own. From the moment they met each other, they impacted each other’s life in a big way. After their encounter both the relationships and characters have gone through major changes.
Both the characters have suffered quite a bit over their lives. Juvia was orphaned for unknown reasons and then bullied on by the other kids at her orphanage due to her rain, which led her to becoming a more depressing character. On the other hand, Gray had lost his family and master to Deliora; haunted by the thought of not being able to protect his family and master caused him to become distant and cold. After their first meeting Gray made the rain that was the cause of Juvia’s loneliness go away and keeps it at bay, while Juvia has slowly but surely softened Gray’s heart.
In the beginning of the series, Juvia was shown to have “stalker like tendencies” like keeping an eye on him in the darkness of the night and making anyone female that approached Gray with even friendliness her rival in love. It was speculated that Juvia’s love for gray stemmed from her lonely childhood, but during the Tenroujima arc all such suspicions were decimated when her love for Gray was shown to be pure and strong enough to even leave her opponent aghast. Whereas, gray has continued his trend of casually ignoring or comically responding to all of Juvia’s approaches. Even in the more recent chapters Gray still gets annoyed and can be oddly cold to her. But Juvias love has only grown stronger for gray over the years, but thankfully the “stalker like tendencies” haven’t. But unfortunately, they have gained some personality tendencies of each other, like Juvia striping in battle and Gray making not so adorable faces at cute things.
The fact that the mangaka has the two fight alongside each other, side by side, holding hands and going as far as to perform Unison Raid’s is the very testament of the trust they place in one another. The moment they perform a Unison Raid is quite a big deal, as Its magic that brings together two hearts! This is a major feat not out done by any other unconfirmed pair in the series. This was referred as a “synchronized attack of love” by Mashima the mangaka himself. Another example would be the “Gray & Juvia Special Chapter” which did not have any relevance to the manga, but has Gray shown to positively respond to Juvia’s affection, even though it was a day of mourning for him.
In conclusion Gray took Juvia’s rain away, and now Juvia is slowly but definitely melting the walls of ice around his heart. Through their differences, they help each other move forward together and that’s why Gruvia is one of the best pairings out there.