Roswaal L. Mathers

Race: Human
Gender: Male
Hair color: Indigo
Eye colors: yellow (left), blue (right)
Height: 186 cm (6'1'')
Weight: around 60 kg

A Margrave as well as an Imperial Wizard and Count who is a benefactor and sponsor for Emilia's bid for the throne. He has strange appearance and voice that Subaru likens to a clown. He is a highly influential individual who is also one of Lugnica's powerful mages.

He is later revealed to have been manipulating Subaru and several other characters for his own goals of killing the Divine Dragon, Volcanica and resurrecting his mentor, Echidna.

During the events in the Sanctuary, he makes a bet with Subaru and loses, forcing him to truly support the Emilia Camp however he still hasn't given up on his ambitions.

After the events of the Sanctuary, he reveals that his soul is the original Roswaal A Mathers and that he has been taking over his descendant's bodies in order to continue living.
(Source: Re:Zero Wiki)