Jonah Orion
Overview
A Blood Ravens Librarian, Jonah Orion first appeared in Dawn of War II. He's notably one of the only non-Salamander marines who is black, leading to a variety of race-based gaiety made by the elegan/tg/entlemen at his expense. The most common explanation for his difference is that Jonah is a highly accomplished Blood Magpie in the force, leading to a reward of excess melanin. That or they looted him from were "gifted" the Brother Librarian by the Salamanders.
In all seriousness, Jonah did not make an appearance during vanilla Dawn of War II, but was noted by Gabriel Angelos to be playing a game of mindfuckery against the Tyranid Hive Mind in order to allow Gabe's fleet to navigate back to realspace. He wasn't alone in the endeavor, unlike SOME mary sues, as it took all of Gabriel's pskers in his fleet to mentally battle the hive mind, but only Jonah remained alive and not driven insane during their mental mindfuckery. He replaced Isador Akios, Gabriel's former librarian buddy, who was unceremoniously BLAM'd by Gabriel on Tartarus (Isadore Akios was blammed not Jonah).
Dawn of War II
Jonah becomes a member of Hairgel's squad in Chaos Rising, appearing in the second mission and melting some twinkly faggots with brain-lightning. If he is corrupted, Jonah gets possessed by a daemon, who notes that the psychic damage caused by the battle with the hive mind weakened his psychic defenses, a fact not helped by Azariah Kyras selling off the cheat codes to bypass the psychic hoods. However, this does mark Jonah as being the only marine who remains pure throughout, and his betrayal is one of the best-written in the whole series. And while the daemon possessing him blusters about damning his soul to the Warp if you kill him, the relic you receive after giving him the only help you can implies that he was wrong, and that Jonah is still able to help you from the other side of death, having grown strong enough to kill daemons just by being in their psychic presence. Not surprising since he fought off the Tyranid Hive Mind, a feat that only one other person can brag about doing.
His body was recovered and placed in stasis, and soon after the Blood Ravens stole- were gifted the knowledge of how to build Librarian Dreadnoughts by the Blood Angels Chapter. The Blood Angels have no record of this happening.
He's also notable for completely shutting down Thaddeus's reason for betrayal, leaving the assault marine without a reply. On the whole, even not taking into account the fact that essentially a psychic Samuel L. Jackson, Jonah is one of the most epic Blood Ravens in the whole series, alongside Tarkus, Gabriel, and Davian Thule.
Jonah is playable in the prologue mission of Retribution, but not in the main campaign itself. He accompanies Gabriel on Cyrene, heading down to Kyras's crater to confront the chapter master. The player's force can find his body next to the building closest to the site of the final battle, making it almost certain that he didn't survive in any race's ending. This means that there's a good chance that all the awesome Blood Ravens are now dead (don't forget their angsty wheel of cheese jerking off somewhere.)
Gameplay
In gameplay terms, Jonah is relatively varied, being able to act as a healer or toss out lightning and fire in bulk quantity, abilities counterbalanced by his fragility and one-man status; both of the other single characters, Hairgel and Davian Thule, are far more hardy. He can also be specced to allow infinite Rosarius spam, by virtue of making it energy-based, or act like a better version of Neroth by throwing free soulfire and smites as part of his ranged attack. Of note is the hilarious combination of empower, which removes cooldowns and energy cost from abilities, with Davian Thule's multi-melta sweep. Powers are acquired by obtaining tomes and psychic hoods, which are tied directly to the perks he has active.
External Links
Even the man who has nothing...