Let's talk about ideas for a moment. Sometimes you read a book and you like the idea so much that you want to write a story with that same type of idea. I don't have a problem with this. Let's be honest, no idea is really original anymore, is it? Nikki Bolvair credits C.L. Stone and her Academy series for the inspiration of Bolvair's Faith series. If you've read both, you can see that they're polyandry stories, but that's about it. So there's nothing wrong with being inspired by stories that you enjoy. 
 When your story starts sounding a little too similar to the source of your inspiration, however, that's where it starts going from inspiration to flat out plagiarism. A huge offender is the Half-Blood series, which has characters and scenes ripped right out of the Vampire Academy series. 
 This is one problem I have with Charcoal Tears. So many things are eerily similar to CL Stone's Academy series (Ghost Bird and Scarab Beetle) that it can't be brushed off as coincidence. 
 Seraph is abused by her father. Sang is abused by her mother (view spoiler)[step-mother, actually (hide spoiler)] in Ghost Bird. Kayli is abused by her drunken father in Scarab Beetle. 
 Seraph is forced to work to support her drunk father and her little brother. So does Kayli. 
 Seraph, Sang, and Kayli all don't have friends until they meets their respective guys, who all fall in love with them immediately. 
 The Academy is the secret organization that Kayli/Sang's boyfriends work for. The Zhevgheri is the secret organization that Miro, Silas, Cabe, and Noah work for. 
 Volto stalks Sang, sneaking into her house, taking pictures of her, calling in bomb threats at the school, all because he wants Sang away from the Academy boys. The Messenger stalks Seraph, doing identical things because he wants Seraph away from the Zhevgheri boys. 
 Sang gets notes in class that are intercepted by her guys. So does Seraph. 
 Sang gets private violin classes with Blackbourne. Seraph gets private art lessons with Miro. These are also the guys that they prefer to confide in, because they're the "leaders". 
 Sang sabotages the guys while they play video games. So does Seraph. 
 Kayli hangs out at her guys' apartments, wearing their boxers and shirts instead of her own clothes. Seraph does this at least twice. 
 Academy/Zhevgheri guys all go on secret jobs, ground Sang/Seraph, keep secrets yet demand complete honesty. 
 No one can tell Brandon and Corey apart except Kayli, and she does it by their eyes. Seraph, despite being completely clueless that Miro and Silas are twins, later says she can tell them apart by their eyes. 
 The GB Academy guys do not engage in romantic gestures with Sang until they're all in love with her and she's in love with all of them, yet this is not communicated to Sang, or the guys who are not clued into the plan until they're in love with her. The Zhevgheri guys do not engaging in romantic relations with Seraph because it will bond them together, yet they don't actually tell Seraph, they just shut down. 
 Sang is taken clothes shopping, where the flamboyant boyfriend, Gabriel, picks out all of her clothes and does a "touch check" with his hands to make sure they fit. Seraph is taken clothes shopping, where the gay, flamboyant cousin, Clarin, picks out all of her clothes and has her strip so he "knows what he's working with". 
 Hell of a lot of coincidences, don't you think? I'd excuse one or two things, sure. Like I said, no idea is original anymore. I'd also excuse all of it in Academy fan fiction, because when you play in said story's universe, you're obviously using the same elements. 
 Even if I didn't read the Academy books before, I was still very bored by Charcoal Tears. There is a supernatural element to the story, yet it is wasted. Nothing is explained, nothing is expanded on, it's just Seraph going to school, hanging out with the guys, and dealing with the Messenger. If you're going to add fantasy elements to a contemporary setting, how about a little more fantasy? 
 Seraph is a lame heroine. I don't really feel like I know her even though we're in her head. Cabe and Noah were flat. Silas was angry. Miro, I did like, though maybe I was projecting a bit of Blackbourne on him, because that's who he reminds me of, if a bit more compassionate and less reserved. 
 The Zhevgheri thing, the pairs, the bonds, the powers, are hardly explained. If you know that this is a polyandry book, you have a basic idea of what the pairs/bonding means. Seraph and all four guys have an identical mark, meaning they are destined to be paired together. Bonding means solidifying that connection. I thought it would be through sex, but apparently it's through really passionate kissing. Seraph has two powers: one she gets from Silas and Miro, the other from Cabe and Noah. Other than that, we basically know zip, because the guys will not tell Seraph. Okay, I gave the Academy guys a pass for not sharing Academy information with Sang (although demanding that she share everything with them is over the line) because she is not Academy, and that is their job. The Zhevgheri, however? That is Seraph's life. She has these powers, she needs these bonds, and keeping her in the dark about it is cruel. She doesn't know why these things are happening to her, and the guys refuse to fill in the blanks. That's just shitty. 
 Charcoal Tears ends with another Academy similarity: the POV switches from Seraph to the Messenger. I hate this. Use third person for the entire book if you want to switch POVs. 
 If you like the Academy series and don't mind a blatant copy, you will probably love this series. If you like the Academy series and despise blatant copying, or didn't like Academy series at all, avoid it at all costs.