Suicidal

Villains who have either attempted to take their own lives, whether they have succeeded in doing so or been overly eager/bold in the face of death. There can be several different reasons for this including remorse, honor, knowledge of worse fates, despair, a greater cause, insanity, nihilism, taking others with them, villainous martyrdom or even redemption. Some of these villains might even be kamikazes, as they may attempt to bring down someone else with them (such as the hero), whether this means actually killing them or simply doing something such as bringing down their reputation. 

Some of these suicidal villains didn't necessarily directly cause their suicides (whether attempted or successful) and were simply eager or bold in the face of death. This includes villains who, when faced with a potentially fatal issue (such as a medical emergency), they didn't do anything to save themselves. In some cases, they might have even attempted to make the issue worse. 

Examples of successful suicides include Vanessa VanCleef (who was trying to take adventurers down with her), the Master (because of a failed plan), the Cassette Man (he stayed in the burning Freddy Fazbear's Pizza, ready to die), Kratos (his suicide is an example of a redeeming one), the Joker (he snapped his own neck after he was paralyzed making the police believe that Batman strangled him to death) and Billie227 (their true identity Laura successfully committed suicide after being severely cyberbullied and returned as a vengeful ghost to kill her tormentors).

Examples of failed suicides include Cell (who tried to blow himself up and take the world with him when defeated by Gohan), the Nostalgia Critic (he attempted suicide several times after watching bad films), Rick Sanchez (who tried to kill himself with a homemade death ray after being dumped by Unity but passed out due to being incredibly drunk before the ray would have killed him), Hyness (who sacrificed himself to revive Void Termina but ends up surviving), Deadpool (who frequently tried to kill himself and finally be with Lady Death yet always failed because of his healing factor) and General Lunaris (who tried to kill himself, all life on Earth and his own Moonlander army by ramming his own ship into Earth, only to be stopped by Penumbra).

It is important to note that if the villain does take their own life, it must be ON PURPOSE to qualify as Suicidal. Villains who accidentally kill themselves DO NOT QUALIFY (e.g. Green Goblin, Will Traeger, Archibald Snatcher, Lord Shen, Mr. Jones and General Mandible). In addition, villains who fake their own suicides and never really wanted to die do not count either (e.g. El Macho and Adrian Griffin).

Many of these villains can be tragic as suicide is portrayed extremely seriously or even sympathetically in both fiction and real-life, so it is no doubt that a majority of these villains have suffered such experiences that have twisted them over the edge of taking their own lives.

However, some of these villains can be Pure Evil as they can also take their lives in an extremely fiendishly selfish or malevolent ways, many of which being where they try to take down the heroes with them, only to fail or even take their lives in a cowardly or egotistical way (e.g. Cell, the Master, Herrscher of the End, General Lunaris and many versions of the Joker).

IMPORTANT: It is to note that even cowards can ALSO qualify for this category. While they cannot be nihilists, cowards can occasionally take their own lives as a way to escape a situation they know they don’t have control over. Regardless, if they take their own life ON PURPOSE, they can still qualify (Samuel Norton is a good example of this).