Silex (シレックス Shirekkusu?), sometimes called Si, is Dr. Hilda Schmidt's second creation and the older "brother" of Scilla. Like the rest of his siblings, he is a combat type Reploid but has an aversion for physical labor.
Following the death of Dr. Schmidt's first creation, she began to work on another project, despite feeling distraught at Sol's fate. It wasn't long until the next Reploid was completed and Silex, yet another combat type, finally awakened after Dr. Schmidt ran a diagnostic to ensure he wouldn't malfunction. Her new creation was a success and displayed no complications. But because of the freewill given to him that all Reploids inevitably possess, Silex grew tired of doing work that required getting his hands dirty. Dr. Schmidt was eventually forced to move him elsewhere where he was used for data management.
After his departure, Dr. Schmidt, despite being disappointed, started on her final creation.