Cocytus

Cocytus (コキュートス, Kokyūtosu) is one of the secondary characters of Isekai Quartet.

Personality
A diligent and loyal Guardian to Ainz. Wishing only to bring him success, even in school. He tells his classmates that those with Ainz should bring victory with him. He also takes his job in Gym seriously, and has those with him work very hard. Stating they should be model people and does not excuse those who don't work hard.

He also shows slight independence compared to the other Guardians. Choosing something he liked and not Ainz during the dodge ball game. Also has a slight tender side when enjoying arts and crafts.

Plot
When the class is split into groups, he is placed in the gym committee with Darkness and most of Tanya's subordinates. He elects himself leader,

Powers & Abilities
A powerful warrior and physically the most powerful Floor Guardian. He has strong armor, knows many techniques, and is very dangerous. He is also capable of teaching others.

Relationships
KonoSuba

Darkness
After Roswaal assigned Cocytus to be in the gym committee with Darkness, Weiss, Koenig, and Neumann; he found her to be "an odd young lady".

During the beach trip, Cocytus had the gym committee plus Grantz to do a thousand push-ups and thought Darkness setting a great example to the men of the Imperial 203rd Aerial Mage Battalion. However, Cocytus realized, "I feel like I missed something."

Re:Zero

Subaru
He finds him to be a true warrior when he refused to peep on the girls.