Scottish studio One Thumb Mobile is expanding.

Now over 20-strong, the developer of mobile MMOG Celtic Heroes has added three senior hires to its Glasgow office.

Product manager Chantal Zuurmond joins from Riot Games, where she worked on League of Legends as associate producer, previously also working on EVE Online at CCP Games.

No twiddling

Animator Andrew Brunton has over 12 years experience including time spent working on the Fable franchise at Lionhead, while character artist Mattia Poderi joins from Bigpoint.

"2013 has been an incredible year for us so far, the continued success of Celtic Heroes has allowed us to build the studio and attract experienced and fabulously talented individuals such as Andrew, Chantal and Mattia," said One Thumb Mobile founder Richard Hasinski.

"All three individuals share our passion to create world beating 3D MMOs for mobile and we welcome them to the team."