Becquerel

The pet and, most likely, the Guardian of Jade Harley. Like most things related to Jade, very little is currently known about him. Also like Jade, he is quite the combo-breaker/psyche, as he is the first non-human Guardian, and all hints pointed at Grandpa to be Jade's Guardian beforehand. He appears to be a dog with the ability to warp time and space to his will.

His full name is, in fact, Becquerel. This, combined with Jade's atom symbol t-shirt, implies that radioactive Uranium will be Jade's associated item in the same manner as John being associated with Oil. It may also mean that Becquerel is in fact radioactive.

Bec can talk or communicate very well with Jade in a similar manner to Jaspers and Rose. When a meteorite landed near Jade's house, Bec didn't want her to go near it, thinking it was dangerous.

Dave

describes Bec as a "fucking devilbeast" that should be "[taken] out behind the woodshed [where Jade should] blow its head off." Jade says she couldn't accomplish such a task if she tried. This has proven to be true as, despite her shooting at him several times with her rifle, he is unharmed; Bec simply alters space - and quite possibly time - to avoid being hit by the bullet in a grandiose manner, such as destroying the bullet the second it touches him or shrinking, then enlarging the bullet transporting Jade and himself on to the bullet to ride it. He also seems to have fantastic speed; not only does he seem to be able to perceive and interact with bullets as if they were barely moving but he can also run ahead of them quite a distance, allowing him to fetch bullets in mid-air. Bec seems to have the ability to mostly, if not entirely, prevent Jade from detecting him with her Gnostic abilities. Jade seems to have no clue as to how he does this, but it's possible that Bec exists outside of time, and thus can't be detected or predicted by precognitive abilities.

Bec is almost undoubtedly Jade's guardian, as he seems to be the only other living being on the island we know of. He was also first seen in very vague ways - first as a carving on a Pumpkin in Jade's garden then as a silhouette in pictures and the background - up until the obligatory introductory Strife scene. Other than upright ears and a canine snout, he lacks a lot of facial features, similar to the other Guardians. He has not yet been shown to have any hobbies that Jade dislikes.