WARNING: The following contains spoilers for Suicide Squad #7, available now from DC Comics.
As a team of supervillains, the Suicide Squad has traditionally been a means for DC's less established characters to take center stage. In issue #7, the team is ambushed by a group who introduce themselves as The Hell Squad, made up entirely of deceased former Task Force X members. This new team makes it clear from the very beginning that their goal is to get revenge against Amanda Waller, the person responsible for the very existence of Task Force X.
Suicide Squad #7 (by Robbie Thompson, Eduardo Pansica, Julia Ferreira and Marcelo Maiolo) continues on the path that the previous issues have laid out. A new Task Force X, lead by Bloodsport and overseen by Amanda Waller are sent on a mission to hell, accompanied by Ambush Bug, a fourth wall breaking teleporter who dates back to the early 80s. While Waller's mission is ostensibly for them to recover the Rock of Eternity, it's clear that she has other hidden plans as well. Before the team can complete their mission, they are overwhelmed by a new team called the Hell Squad. Although both teams are united by a shared enemy, their backgrounds and abilities could not be more different.
Blackguard
Although Blackguard recently debuted in the DCEU in James Gunn's film The Suicide Squad, his comic book counterpart dates back much further and has less in common with the version seen in the movie. Blackguard, aka Richard Hertz, was first introduced in Dan Jurgens' Booster Gold #1 in 1986 as a villain to the heroic time traveler.
Hertz was later recruited by Metropolis based Criminal Organization The 1000, who gave him the power to create energy constructs. Blackguard was unceremoniously killed in 2008's Suicide Squad #7 (by John Ostrander, Javier Pina, and Jesus Saiz) and had not been seen since. He will likely serve as a major physical threat for Task Force X going forward.
Branch
Branch is a character with a much less expansive history. He's a metahuman with plant-based abilities, including the power to hear their thoughts. Branch was introduced in issue #3 of the current series as a reluctant member of Task Force X.
In his short time on the team, Branch made clear his disinterest in combat or criminal activities, going so far as to cower and beg for help during a mission, leading to violent retaliation by the leader of the squad, Peacemaker. He last appeared in issue #6 where he was killed by Ultraman, the Kal-el of Earth 3. His commitment to this new mission is a seemingly uncharacteristic development.
Cavalier
Cavalier (Hudson Pyle) is a character created by James Robinson and Tim Sale for their 1992 series Legends of The Dark Knight, although he has more recently been folded into main DC continuity. He has no traditional superpowers but is skilled at fencing, having even beaten Batman.
Cavalier was killed in 2019's Suicide Squad #1 (by Tom Taylor, Bruno Redondo and Adriano Lucas) while Task Force X attempted to infiltrate a group of revolutionaries. Though it is not clear what purpose he will serve in the future, his presence certainly seems to imply that the Hell Squad exists as an answer to Amanda Waller's flippancy towards death.
Mad Dog
Mad Dog (Rex) was introduced in 2011's Suicide Squad #3 (by Adam Glass and Cliff Richards) as an antagonist. He was initially a member of the League of Assassins before being folded into Talia al Ghul's Leviathan organization. He works as a bounty hunter and has a design that invokes both Deadshot and Deathstroke.
Following the events of his first appearance, he later joined the Suicide Squad. This eventually led to his death in the Suicide Squad: War Crimes Special (by Ostrander, Gus Vazquez, Carlos Rodriguez and Gabe Eltaeb). Although Mad Dog has yet to reveal any supernatural abilities, he is highly formidable and dangerous by virtue of his background.
Mindwarp
Mindwarp (Peter Howard) is a character who was initially introduced in issue #2 of the current series. He is a telepath with the specific ability to control the minds of others and bend them to his will. While this is not an uncommon power, his position as a villain introduces a different sense of threat.
Howard was killed during the A-Day attack on Arkham Asylum, when the facility was flooded with Joker Toxin. There isn't much known about his character but he seems to have taken a leadership role on the Hell Squad. This also introduces interesting potential applications for his power.
Slipknot
Slipknot (Christopher Weiss) is a character with a much longer history than most of the team, having been first introduced in The Fury of the Firestorm #28 (by Gerry Conway, Joey Calavieri and Rafael Kayanan). Although he died shortly after that first appearance as a member of Task Force X, he was active again until 2011 when he was killed by the Tattooed Man.
Weiss' abilities are derived from the ropes that he developed and trained with, using them to become a dangerous assassin, alongside his general combat prowess. The character appeared in the 2016 Suicide Squad film where he was portrayed by Adam Beach and suffered an almost immediate death.
Weasel
Weasel, like Slipknot was initially introduced as a Firestorm villain. Formerly a widely disliked student of Martin Stein, his power and threat comes from his vicious and animalistic nature, which is also the reason he was inducted into the Suicide Squad.
Weasel was killed in 1988 in Doom Patrol and Suicide Squad Special #1 (by Ostrander, Paul Kupperberg, Erik Larsen and Carl Gafford) and was not seen again until now. Similarly to Blackguard, Weasel was featured in The Suicide Squad where his feral stupidity was framed mostly as a joke. However, in the comics, Weasel is unpredictable and poses a unique threat as a member of the Hell Squad.