Thanatos is a enemy from the Resident Evil series of survival horror games. It was a unique Tyrant specimen created by rogue Umbrella scientist Greg Mueller in the game Resident Evil Outbreak. During the Raccoon City Outbreak, Greg released Thanatos in defiance of Umbrella's mass-production of Tyrants.
Thanatos was easily recognized by its sublime display of agility, brute force, and keen survival instincts. While chasing the survivors throughout the University, Thanatos displayed its quickness, easily outrunning all the survivors. Thanatos could quickly kill by simply stabbing its claw into a victim. It was completely impervious to all small-arms fire, and the only known way to cause it harm was an intense dose of electricity. All this culminated into forging Thanatos into a perfect killing machine.
After it was weakened by the University's collapse, it went through a mutation that severely diminished its strength. Upon becoming Thanatos-R, it became characterized by its towering height; over 12' tall, a bigger and beefed up body, a single massive claw, and the loss of one arm.
During the outbreak, Greg formed a partnership with Peter Jenkins at Raccoon University with the offer of aiding him create a vaccine for the T-Virus. T-Blood, blood from a creature infected with the T-Virus, was offered by Greg to be obtained to create the anti-virus. Greg had it in mind to get the blood from Thanatos. However, Peter discovered that Greg was helping him create the vaccine purely due to a personal vendetta, and that Greg actually sought to use the cure as leverage against Umbrella. As such, Peter refused to continue researching with him, and thus T-Blood from Thanatos was rendered useless. Thanatos, however, would not remain dormant.
A U.B.C.S team was sent by Umbrella to Raccoon University to stop Greg. In response, Greg released Thanatos to deal with them. In the Back Square, Thanatos ruthlessly and efficiently eliminated all but one member of the squad. This surviving soldier, Nicholai Ginovaef, managed to inject Thanatos with a device that collected a sample of its blood. In fact, it is possible that this is what threw Thanatos into its rage, as it did not attack until being injected. Nonetheless, Thanatos carried off the body of a U.B.C.S soldier to Greg for his researching purposes, as he was found in his laboratory. An Umbrella Biohazard Countermeasure Service team was sent by Umbrella as part of Operation: Emperor's Mushroom. The objective was to enter the grounds of the Raccoon University and retrieve the Tyrant, or if the creature was too strong to contain, kill it and retrieve the remains. The operation was ready to go ahead from 0535 to 0635 on October 1, 1998, the very last moments available for the company.
Thanatos next pursued a group of survivors throughout the University, possibly through direct command by Greg. Whatever the reason, it failed, and the survivors managed to escape its grasp. In fact, the survivors temporarily managed to knock Thanatos out with an electric shock. After Greg's death and the activation of the C-4, Thanatos again tried and failed to catch the survivors while they fled. While they escaped to the temporary safety of the Back Square, the C-4 went off, destroying the University and bringing it down around Thanatos. Though this severely injured it, and cost it an arm, it also caused it to mutate into a monstrosity known as "Thanatos-R."
After its mutation, Thanatos resumed its chase for the survivors outside the University. As they made their way to evacuation, Thanatos cut them off. Though it easily overpowered the survivors, they managed to procure a rocket launcher from inside a locker, which managed to weaken Thanatos even more. Still, Thanatos quickly resumed its chase at full strength. At the Front Square, Thanatos intercepted the survivors for the final time. They utilized an Ampoule Shooter dropped by a dead soldier. By inserting a sample of Daylight into it and shooting it into Thanatos, they finally defeated him and escaped. It is possible for him to survive the daylight injection as it was shown in the Kevin and Jim scenarios. Also, it is unknown whether Thanatos was killed in the final battle or was just knocked out and then destroyed by the missiles fired at Raccoon City.
Thanatos appears as a boss.
Thanatos is one of the most powerful Tyrants. In its first form, it is unkillable, fast, and does not filnch very easily: even when the building collapsed on top of it, it just severely weakened it, forcing a mutation and new abilities such as leaping great distances and broad attack patterns form its extremely long arm. Despite having the exposed heart which Tyrants are characterized by, it does not seem to be a weak spot as it is with other Tyrants. Thanatos is also one of the Tyrants who can survive a direct rocket launcher hit. Thanatos did however demonstrate two weaknesses in its activity. Firstly, it was sensitive to jolts of electricity and could be knocked out. As with other Tyrants, its grafted animal heart was left exposed, though until its Super Tyrant mutation this was covered by a metal casing.
During its standard form, Thanatos is the only Tyrant that can make instant death attack even in "FINE" status. The player will notice this action as it will stay standing still in the place and start groaning, stabbing any character on its way.