- Localized Name: Mikleo
- JP Romanized: Mikleo
- JP: ???? (mikurio)
- Age: Unknown
- Height: 165 cm
- Weight: –
- Designed by: Mutsumi Inomata
- Race: Seraph
- Weapon: Staff
- Voice Actor:
- JP: Ryota Ohsaka
- English: Michael Johnston
Mikleo is a water seraph who has been friends with Sorey since before they could walk. Mikleo is Sorey’s best friend and complements him by grounding Sorey’s wild ideas and behavior and offering him frank advice as needed. He acts as both a friend and a rival to Sorey, and is more calm and composed compared to him, though he can easily get riled up with the right push of the buttons. His insistence on an archaeological perspective different to that of Sorey frequently leads to arguments between the two of them. Though Mikleo’s small build makes him appear childish, his speech and conduct do anything but.
Being a seraph, Mikleo is invisible to regular humans with the exception of Sorey. As such, Alisha is the first human Mikleo actually meets after Sorey, though Alisha does not perceive him at first because of her inability to see seraphim.