|“||Please do try to fulfil my request, Hyoudou Issei. Allow this god of death to witness your full power.||”|
Thanatos is the strongest Grim Reaper and one of the oldest Executive-class Grim Reapers who leads his own faction in opposition to Hades.
Thanatos wears a skull mask and an exquisitely decorated cloak, the standard of all Grim Reapers.
Thanatos is calm and reserved, even giving his opponents respect when he complimented the transportation magic circle technique used against Loki, used on him, as being quite a clever technique. When his comrade Pluto was defeated by Vali, he commented that Pluto shouldn't have felt dissatisfied with touching the power of a Heavenly Dragon, showing his small fascination with fighting powerful opponents. He also has a rebellious side because as mentioned by Orcus, he hardly follows Hades' orders and often takes actions against Hades’s will. Despite his rebellious side, it was all just merely to avoid Hades finding out the secrets of creating artificial Super Devils and hates Hades of doing something nasty things again. This can be assumed that his intentions are good, yet his actions are still harsh and out of the line.
At some point, Thanatos was created by the Greek Primordial God siblings, Erebus, the God of Darkness, and Nyx, the Goddess of Night, soon becoming the strongest Grim Reaper and one of their main pillars.
Red Dragon Emperor of the Blazing Truth × White Dragon Emperor of the Morning Star: The True Dragon(s) of the Kuoh Academy
In Volume 24, Thanatos sent his subordinates to capture Koneko to obtain her hair clip which contains research data on creating Super Devils, to try and prevent the data from falling into Hades' hands. He officially appeared himself later on above Fafnir Stadium while the match between Team Rias Gremory and Team White Dragon Emperor of the Morning Star was going on, due to his subordinates attempts to interrupt this match having been thwarted. After he appeared above the stadium, he was transported to a wilderness area a far distance away, trapped inside a barrier erected by Rossweisse and Grayfia, engaging in a fight with Issei who was waiting for him. During the fight, Thanatos was outmatching Issei until Issei was aided by his grandfather Juzo, Guatama Buddha, and Guanyin, where Thanatos was finally defeated by Issei's Nyuutron Beam Cannon.
Powers & Abilities
Immense Strength: Thanatos is regarded as the Strongest Grim Reaper among Ultimate-Class Grim Reapers, a single swipe from his scythe could change the terrain inside of a barrier. Ddraig noted that Issei would have no chance against Thanatos using Cardinal Crimson Promotion or Partial Dragon Deification. In fact, Thanatos has power rivaling even some God-class beings and could keep up Issei using D×D Form.
Immense Speed: Thanatos has tremendous speed, being able to create several afterimages of himself and also surpass even Issei using Pseudo-Diabolos Dragon God, sealing his cannon in almost the same moment.
- Replication: Thanatos is fast enough to create several duplicates of himself from his afterimages, which could surround Issei and grant them a physical presence, allowing them to attack his opponents.
Magic Expert: Thanatos has some skill in magic.
- Sealing Magic: Thanatos demonstrated the ability to use sealing magic as he used a sealing technique to seal Issei's wing cannons.
Master Scythe Wielder: Being the strongest Grim Reaper, Thanatos' skills in wielding scythe is exceptional among the other Grim Reapers.
Flight: During the events of Volume 24, Thanatos has demonstrated the ability to stay afloat in mid-air.
Death Scythe: As any Grim Reaper, Thanatos' scythe can wound his opponents and shorten their lifespan with a special type of curse but as the strongest of them, his is much stronger than that of the other Grim Reapers, even Pluto's. His scythe itself is also clad in a potent aura.
- In Greek mythology, Thanatos is the personification of "Death".