|Name in Japanese||ケルベロス・ワンサルド|
|Romaji Translation||Keruberosu Wansarudo|
|Nickname(s)||Watchdog of the Underworld|
|Voice Actor (Japanese)||Hiroki Yasumoto|
|Voice Actor (English)||Mark Stoddard|
|Classification||Megalo (Head of Doberman)|
|Debut (Anime)||Episode 04|
|Debut (Manga)||Chapter 05|
|Appears in||Light Novel, Anime, Manga|
Kerberos Wansard (ケルベロス・ワンサルド, Keruberosu Wansarudo?) is the "Watchdog of the Underworld" with the body of a man and the head of a Doberman whose job it is to make sure that all of the souls that enter the Underworld never leave. He is an acquaintance of Eucliwood Hellscythe, and seems to respect and care about her a lot.
He is a Megalo which has the duty of ensuring the proper flow of souls from the living world to the Underworld. He arrives at the Aikawa Residence in search of clues related to a serial killer who has been offering souls and disturbing the balance of souls in the two worlds and ultimately dies in the hands of the serial killer.
Like most Megalo, Kerberos takes the form of an animal, which in his case is of a dog of the Doberman Pinscher breed, although he walks like a human. He wears a trench coat over his gakuran, the same outfit that is characteristic of Megalo, and a soft hat. His appearance is similar to the stereotypical appearance of a detective.
Kerberos is rather strict when it comes to his duties, and has shown little regard to the lives of humans if he deems them as obstacles to his missions. However, he has shown a more friendly personality when it comes to Eucliwood Hellscythe and her friends.
Visitor from the Underworld
Kerberos arrives at the Aikawa Residence as part of his investigation of the nearby neighbourhood. He was dispatched to the living world after cases of souls not crossing over to the Underworld have been reported. He initially showed force against Ayumu Aikawa, but he ceased his attack after discovering that Ayumu is a friend of Eucliwood, whom he is familiar with.
He later introduces himself over some tea and reveals his purpose for arriving in Ayumu's neighbourhood. He also tells about Eucliwood's powers and the effects of its usage, reminding them that her use of her reality-warping abilities can cause her great pain, even for a simple healing spell, which Eucliwood used on Ayumu after Kerberos' attack earlier. Ayumu decides to join Kerberos, as he also is on the search for a serial killer that might be the same target as Kerberos.
In one house during their search, Kerberos and Ayumu were attacked by an unknown assaulter. Kerberos is fatally wounded during the attack, and he urges Ayumu to escape while the killer hasn't made another move. It is assumed that he died in the attack.
- Cerberus is the name of the three-headed dog which watches over the gates of the Underworld.
- As a cerberus is originally a three-headed dog, his last name "Wansard" can mean "one third", due to him only having one head as opposed to three.