Hi! LOGH is full of awesome cast  when we talk about seiyuus. The characters I've placed here are my personal favorites. If you want to know, I'll tell you which other roles those seiyuus have portrayed. 

\-Bittenfeld \[Portrayed by Keiichi Noda, seiyuu of Cepheus Albiore (Saint Seiya), Tetsuya Tsurugi (Great Mazinger)\]

\-Reuenthal \[Portrayed by Norio Wakamoto, seiyuu of Cell (Dragon Ball Z), Chiyo-chichi (Azumanga Daioh, the famous meme cat who says "HARO EVERYNYAN!")\]

\-Fahrenheit \[Portrayed by Sho Hayami, seiyuu of Gavlet Gablae (Heavy Metal L-Gaim), Ginias Sahalin (MS Gundam the 08 MS Team)\]

\-Yang \[Portrayed by Kei Tomiyama, seiyuu of Duke Fleed (Grendizer), Tomiyama has been known for playing roles on Live Action movies for actors like Martin Sheen and Woody Allen\]

\-Oberstein \[Portrayed by Kaneto Shiozawa, seiyuu of M'Quve (Mobile Suit Gundam), Rei (Hokuto no Ken)\]

\-Frederica \[Portrayed by Yoshiko Sakakibara, seiyuu of Haman Karn/Mouar Pharaoh (Zeta Gundam), Queen Nehellenia (Sailor Moon)\]

\-Reinhard \[Portrayed by Ryo Horikawa, he played roles like Vegeta (Dragon Ball Z), Kou Uraki (Gundam 0083\~Stardust Memory)\]

\-Kessler \[Portrayed by Shuichi Ikeda, who played Char Aznable, the iconic character from Mobile Suit Gundam.\]

I could mention a lot more like Kazuhiko Inoue (Dusty), Katsuji Mori (Mittermeier), Takaya Hashi (Mecklinger). 

I haven't watched DNT so I don't have much references about the cast.

In your opinion, who is your favorite voice?