Iris

The Black Dragon Iris was an acquaintance of Gaia. Now she is a member of Mathias' party.

Iris has a very calm personality, but even so, she acts childish sometimes and even goes overboard when using magic. She doesn't get human tendencies yet, so she doesn't know when to hold back or what emotion to use and if she is doing the right thing or not. She's not that smart, either.

(Source: Shikkaku Mon no Saikyou Kenja Wiki)