He is Teletha's older twin brother and a high-ranking member of Amalgam. He is the series' primary antagonist and an arch nemesis to both his sister and Sousuke. His personal Arm Slave is Plan-1055 Belial. He is a child prodigy and a Whispered. Within Amalgam, Leonard is known as "Mr. Silver" and is part of the upper circle. It is understood that his superior Whispered intellect has both generated and proliferated the organization's Arm Slaves, Lambda Drivers, TAROS and other Black Technology weaponry.

This series is set about two months after the events ocurred in the Tuatha de Danaan at the end of the original series. Mithril becomes aware of a secret organization that has technology able to counter the ECS (Electronic Cloaking System) mode. This organization, known as Amalgam, also has "Black Technology", obtained from "Whispered" like Kaname Chidori, and like the other intelligency agencies, they intend to obtain more. However, when Sousuke's mission to protect Chidori is terminated by Mithril, all seems to be in place for Amalgam's plans... Like many of its fans know, it is based of the FMP novel "The End of Day by Day."
 
(Source: Anime News Network)

__Alma Mater:__ Tokyo International University

[Website](https://kiramune.jp/artist/namikawa/) | [Twitter](https://twitter.com/namidai0402) | [Blog](https://ameblo.jp/namikawa--daisuke) | [YouTube](https://www.youtube.com/channel/UCgrXnEIrI4LLgVYzGoQvJcg)

Blake Thomas Shepard is an American voice actor who works on anime series at ADV Films, Funimation and Sentai Filmworks. 

Nine months have passed since teen soldier Sousuke Sagara first became Kaname Chidori's covert protector. In that time, Mithril has been remarkably successful at thwarting Amalgam's efforts, but this has only made Amalgam more determined. Leonard Testarossa's visits with Tessa and Kaname are just preludes to all-out attacks that begin with global communications disruptions. Kaname's status as a Whispered makes her one of Amalgam's main targets, which means that any semblance of a peaceful life at Jindai Municipal High School is now over for her.
 
(Source: Anime News Network)

Tells the same story as Full Metal Panic Second Raid and is as such, also based on the novels The End Of Day By Day. 
Leaving off after the original series, this series tells of Sousuke and Mithril as they fight Amalgam. Like the original series, but both sides have gotten a bit more aggressive...

Jindai High School was a relatively safe place, right up until Sousuke Sagaka transferred there. A total nut, he wreaks havoc on the school's student body and gets into a world of trouble with the teachers! But there's more to Sousuke than meets the eye&mdash;not just a hell-raising student, he's actually a member of an elite military unit, on an undercover mission to protect the beautiful schoolgirl Kaname Chidori from the KGB. 
(Source: Tokyopop)