By the end of the series he seems more accepting of it. When the series renewed they seem to have worked out a brother-sister version of a Two Girl Romantic Friendship. However Mimi is also his crush so there could be a love triangle in the works...
Brought Down to Badass: Offers up his demon powers in the non-canon sequel story Afterbirth in an attempt to regain his sister's love. It works.
Dem Bones: A living skeleton like his father. His spirit form is more human looking though. Because he was originally human, but Grim's plans called for killing him and bringing him back as a reaper.
Driven by Envy/The Resenter: Towards Minnie, combined with The Unfavorite. He also hates that Nergal Jr. (his godfather) shows more attention and love towards her, though it is later justified as Nergal Jr. is Minnie's biological father.
Future Badass: From the Afterbirth previews, he seems to have gotten far more skilled, though this story was later "de-canonized".
Go Through Me: After Mandy drains the dark energy out of Mimi, reverting her to her human form and orders her to be disposed of. Junior, tired of her callousness, stands in front of Mimi and refuses to move even when Mandy starts physically beating him.
Grew a Spine: Pun aside, he made a daring choice to summon his demon-reaper powers to defend a weakened Mimi from a pissed-off Mandy. It's also because he made that choice that Mandy actually decides to spare Mimi.
Good Girl Gone Bad: After she realized that her brother is growing more and more distant from her thanks to her mother's speech; she now has reinveted herself to honor her name and be a mini clone of her mother.
Incorruptible Pure Pureness: Surpricely for the Underworld's princess and Mandy's daughter, Minnie is kind, demure and pretty much the perfect little girl. She's too much that pure, that her soul was acceptable for heaven and a high rank angel descended specifically to escort her. After The Reveal about her feelings for her brother, however, her pureness does actually corrupts to the point of being true to her name and becoming a mini Mandy.
Kick the Dog: The first thing she does after reinventing herself at her mother's image is critize and stoomping over her brother's muffins.
Has now crossed over into endangering Junior's life as well as of the latest comic.
The very same from The Grim Adventures of Billy & Mandy. In this universe, after years of unwilling servitude to the two title characters, he found he actully did like hanging around them, especially Mandy. At first he was unwilling to kill them, allowing Mandy to live into adulthood. He eventually gathered the nerve to reap her, but not before proposing to her first. She accepted and the two have the ruled the underworld since.
Dark Is Not Evil: He's the Grim Reaper, his very purpose is to reap souls and take them to the other side, whichever that may be. That said, he is not a bad guy. He genuinely loves his children, and he wishes for peace among the other rulers of the underworld. The only really evil thing about him is that he has no problem with death as he is the one reaping them anyway.
Even Evil Has Standards: He actually calls Mandy out for letting Mimi get close to the Hand of Horrors knowing full well what it can do.
He gives another to her for not helping Blossom and Mimi during their hour of need in the past
Papa Wolf: Loves his kids very much and will do anything to protect them.
Grim's wife and mother to Junior and Minnie. After years of bossing Grim around, she found out he had grown an attachment to her and Billy. As such, she was immortal since he kept prolonging her life and she grew into powerful woman until Grim finally gathered the nerve to reap her. She married him instead and became ruler of the underworld alongside him. She had an affair with Nergal Jr. at one point which resulted in Minnie, which Grim was aware of, though he wasn't happy about it.
Really Gets Around: Junior's biological father was a human man (whose identity, as of this writing, is unknown), and she also slept with Nergal Jr. which produced Minnie. And later Dark Danny, which results in the twins Dani and Manny.
Justified, as Grim is incapable of creating life, and it's implied the only way Grim can have a child is through an abortion, stillbirth or miscarriage. This is how Junior was born as a reaper and not a normal human.
"The Reason You Suck" Speech: Makes it perfectly clear to Minnie in "The Weight of Lineage" that for all her Purple Prose and a "killer" Death Glare, she lacks her mother's ability to take action without hesitation or remorse, and that Junior will keep "flying further and further" out of her reach until she does so. A point which is exemplified by The Reveal that Mandy was the one who shot the line holding Junior and Mimi, not Minnie.
Two new additions to the Grim household born in between the end of "What About Mimi?" and "Afterbirth''. They are the product of Mandy and Dark Danny sleeping together. As such they have ghost powers. Due to "Afterbirth" being ruled non-canon, their future in the series is in doubt, though "Elements lifted from Afterbirth may manifest in the official work later, in some form", so they may still appear, especially given Mandy's sleeping with Dark Danny in "What About Mimi?".
Silk Hiding Steel: Because she lacks her other siblings' sheer battle powers, she comes across as this.
Synchronization: When Dani was under Drax's power, Manny could feel her pain miles away and track her.
Weak, but Skilled/Unskilled, but Strong: Dani knows a lot about the non-combat powers she has, but seems to lack her brother's sheer strength. Manny is the exact opposite with barely any understanding of his non-combat powers, but he can already preform a ghostly wail and can unleash powerful ecto blasts.
Worthy Opponent: Dani seemed to show respect for Empheles, to the point of staring in shock after his core detonated.
Allies and Extended Family
The temporal ghost from Danny Phantom. Acts an an observer and guide to Junior during his spiritual trip. Hinted that he knew what was to come (he a ghost of time after all). Grim doesn't seem to like him much.
Danny Phantom's evil future self from The Ultimate Enemy. Clockwork released him in preparation for the coming events, with the threat that he'll erase him from existence (as D.D. exists outside of time now due to Danny's actions in the movie) if he gets out of line. Helps to fight against Minnie's monster form.
Ax-Crazy: His demeanor seems to have slightly deteriorated from his stay outside time.
Actually, he was this combined with Omnicidal Maniac before going outside of time. If anything, he's more mellow compared to his previous actions.
Anti-Hero: Really just in it cause he has no choice.
Badass: Let's face it. To stand up to an Eldritch Abomination and actually subdue it when the entire army of the Underworld couldn't, you earned this title.
Jerk Ass: The biggest in the series. Though compared to how he acts here in the comic to how he was in the show, it's clear his imprisonment (and Clockwork's threat to erase him from existence) have greatly mellowed him out.
Grims/Mandys General and Leader of the Castle Guards. He may actually be Juniors biological father. This is hinted at when he losses his helmet in What about Mimi as his face and Juniors look very similar.
Undying Loyalty: Both figuratively and physically as he won't die unless Grim lets him.
Real Men Wear Pink: Has Tattoos of Mandy on his back (used to be of Grim but changed in the original series)
An otherworldly creature who has relations to Grim and Mandy. Comes to help out when Minnie's monster form runs rampant. Also has bad blood with Grim. The one present though seems to just be a spiritual apparition connected to the real one.
Him and Blossom's daughter. At first a voiceless and armless girl whom Junior meets while wandering a frozen tundra. However this turned out to be a trap of Him to lure Junior to him. Once revealed, she transforms into a more devil like creature. She turns against Him and helps Junior and Minnie escape once Jeff is threatened.
Abusive Parents: How abusive? He cut off her hands and psychologically tortured her.
Gilded Cage: The Nephilim. It maximized the effectiveness of Mimi's precognitive abilities to stop meta-human crimes and protected her from all manner of attacks, but drained her in every way. She'd be completely helpless if separated from the machine. While Dexter didn't like it and lampshaded her position as a "caged bird", he kept her protected for the sake of the superhero community. This being Mimi's flashback, we know howthat turns out.
Morality Pet: Manny seems to had touched Mimi's tiny heart somehow, since she went to rescue the twins instead of going at Junior's aid at first. Also picked his cheek and give him a gratuitous Marshmallow Hell.
Powered by a Forsaken Child: Before she became Her, Mimi's high-level telepathy meant that she was hooked up to a machine that magnified her abilities, making her a preliminary warning system for the heroes of the world whenever a meta-human was about to commit an evil act. The machine drained her physically, mentally and spiritually, which explains why she's wheelchair-bound and barely able to speak in her Hands of Horror-induced flashback.
Puppy Love: A few panels suggest that she and Junior like each other. And they do have an Almost Kiss at one point, but this is never focused on.
Self-Made Orphan: In GTFO, it's revealed that she was the one who killed Blossom. Him has a picture of the event hanging in his office
The Voiceless: Usually she spoke while under the influence of The Hand Of Horrors, and is implied to have fallen mute after being tortured by Him.
Jeff the Spider
Billy's "son" and Mimi's Nanny. Due to this he is at service of Him as he hopes Him can grant his wish of having his "father" love him. Despite this though, he still kind to a fault which plays a role in Junior and Minnie's escape from Him.
Anyone Can Die: In the WhAM comic "Making Headway", a flashback is shown that Him decapitated Jeff right in front of Mimi. It might be a case of Kill the Cutie if he weren't, you know, a giant spider.
Heel-Face Turn: He was always a nice guy, so this came as no surprise.
It is somewhat difficult to distinguish between 'heroes' and 'villains' at this point, as almost all of the currently active characters are despicable in some way or another. Junior, Jeff and ironically Death represent rare exceptions to this rule.
Lock, Shock and Barrel
The resident mischief makers of Halloween Town as well as Ooogie's minions. They befriend Junior while he mucking around by himself, who would later go on to explain how his parents got together to the three. However the whole thing is a trap to lure Junior to Oogie so he can take Junior hostage. The plan almost works, but they don't expect Minnie to come to Junior's rescue nor Ooogie actually murdering her. And especially don't expect Junior gaining Minnie's powers and using it to rip out their souls.
My God What Have We Done: Judging by their expressions when things hit the fan. They didn't really expect Ooogie to actully kill Minnie.
A evil resident of Halloween Town who is trying gain the title of the most scariest creature. However upon hearing that the Grims were in Halloween Town he changes his plans to try to usurp his position by kidnapping Junior and holding him hostage. Minnie comes to his rescue instead and easily handles Ooogie But thanks to Junior's callousness at being rescued by her, it gives Ooogie time to catch Minnie off guard and kill her. This however had the repercussion of Junior gaining her powers and using it to absolutely annihilate Ooogie.
Moral Event Horizon: Well lets face it, Oogie was already a prick. But killing Minnie cemented how far he was willing to go.
The second baddie that Junior comes across (this time during his spiritual trip) and one of the PPG's toughest foes. He too is also after the power of the Grim family since he is at odds with them for the position for the underworld. As such he takes over Minnie's spirit and tries to use her to kill Junior. Things don't exactly go as planned however. When that plan goes south, he sends his daughter Mimi into the Grim family household to retrieve something for him which was revealed to the Hand of Horrors (as seen in the B&M movie The Big Boogie Adventure).
Abusive Parents: He cut off his own daughter's hands. And in the WhAM comic, he then beheads Jeff in front of her and threatens to torment his soul if she doesn't do what he says.
Taken even further in the GTFO comic. Before he cut her hands off, he made her kill her own mother
Adaptational Sexuality: Kind of. In the original series, Him's attire and speech pattern was more feminine and is Camp Gay. The web comic version dresses more masculine and is willing to physically do his own dirty work.
Taking You with Me: Grapples onto HIM and pulls a grenade calling for Raven teleport them away from the battleground where all three are caught in the explosion. Seeing how this is a flashback, it obviously didn't work.
Raven: HEY! THAT'S ENOUGH OF THAT! Your mom's busy trying to keep the world safe, which entails that she's out there trying to keep you safe! So get that through your head and stop throwing a fit like a spoiled little brat! You're a year older already, so grow up!
Fridge Horror: In Mimi's flashback, Grim states that because of the traitor in the midst of Megaville's heroes, only a ragtag group of heroes (Irwin, Hoss Delgado, and Raven) remained to fight off evil forces. The fact that Raven was one of the last three remaining heroes against Him implies that none of her friends survived with her up to that point.
Honor Before Reason: Him offered Raven a chance to join his side so she can take care of Mimi while he handles his "hectic schedule". Raven knows what his plans for Mimi are if she surrenders and succinctly tells Him off.
Young ward and friend of Count Vlad, now a vampire-in-training after being bitten by him, but apparently not by choice. Signed a contract with Him and fought Mimi in a battle where winning would mean she regained her human life/soul, but lost and forfeited the Count's castle according to Him's terms.
Broken Pedestal: Considering the main series where she practically adored Vlad as a child, him turning her into a vampire against her will has certainly disillusioned her over the years.
Calling the Old Man Out: With a touch of What the Hell, Hero?, when she calls out Vlad on turning her into a vampire against her will and trying to gloss it over by training and teaching her his ways, thinking she'd forget about her old life.
Curb-Stomp Battle: Despite Mina pulling out a number of impressive transformations during the fight, Mimi pretty much had her number from the start.
Our Vampires Are Different: Played straight in terms of the qualities of a vampire that Vlad has. She has his strengths (Transformation, immortality, flight, etc.) and his weaknesses (Garlic, aversion to sunlight, need for life sustenance, etc.).
Red Eyes, Take Warning: Played straight during the fight with Mimi, but inverted while confronting the Count about her immortality; the latter is less evil and more a mix of frustration and sadness, tinted slightly by anger.
The Ageless: Not necessarily 700 years old, but Mina's been stuck in the undead body of a seven-year old long enough that's it made her yearn for human life again.
What the Hell, Hero?: He scolds Mina like a bad child for going behind his back by wagering his castle in the fight with Mimi, only to have it turned around on him by Mina, who calls him out for treating her like a child when she's anything but and turning her into a vampire at a young age, more or less against her will. Of course she's accounting from her perspective, for all we know it might have been an Emergency Transformation.
Even Evil Has Standards: Played straight and subverted in a sense. Hunson feels Him "really messed up" Mimi, but understands that he's preparing her for the "family business" like Hunson has tried to do with Marceline.
Understatement: After verbalizing all of Mimi and Him's "actions" in the office photos, including Him making Mimi kill her own mother, Hunson makes one for the century.
Flashback Cut: Experiences one as she gazes into the portrait of Blossom and Mimi. Horrifically subverted, as it's not a memory of Chi's, but a rather shocking vision of Blossom's final moments (from her POV, no less) before dying at the hands of her tear-stricken daughter. Hinting at her maybe being a reincarnated Blossom.
Woman Scorned/Psycho Ex-Girlfriend: Though we don't know how...close they were, Chi seems to have an insane thing for Mimi and went crazy just for the thought of Mimi seeing someone else when she didn't reply to any of her 405 messages.