From Lexicanum

Mattius Heiron is an Inquisitor of the Ordo Malleus.

Preface

On Cordassa Heiron was in search of the Liber Nefestum, a book about chaos-sorcery he wanted to snatch from the following of chaos and use it against them. It came to an implicit rivalry with Artemius Grohm, as Heiron thought the Dark Angels also to chase after the artefact.

After the incidents on Marakross Heiron, who got wise to the Dark Angels by Borroleth, swore to discover their secret.

Sources

• Tales from the Dark Millennium (Anthology) - The Falls of Marakross (Short Story)