Dragon Quest Heroes confirmed seiyuu

Every Dragon Quest characters until 7 before have recorded in Drama CD. Wikipedia link.
Drama CD actors are feet on old version, Dragon Quest Heroes has latest and usually used actors.

Example: Maya (DQ4) - Miyuki Sawashiro instead of Michie Tomizawa.
Hikaru Midorikawa has voiced Terry (DQ6) in Drama CD, but his role is changed to Kiryl (DQ4) instead of him.

Original characters
Akuto (Male protagonist) - Tori Matsuzaka
Meer (Female protagonist) - Mirei Kiritani
King Dirk - Banjo Ginga
Julietta - Mikako Komatsu
Homiron - Rie Kugimiya

Series characters
Alena (DQ4) - Shoko Nakagawa
Maya (DQ4) - Miyuki Sawashiro
Kiryl (DQ4) - Hikaru Midorikawa
Teery (DQ6) - Hiroshi Kamiya
Jessica Albert (DQ8) - Ayana Taketatsu
Yangus (DQ8) - Fumihiko Tachiki
Bianca Whitaker (DQ5) - Marina Inoue
Nera Briscoletti (DQ5) - Kana Hanazawa

Torneko is voiced by Tessho Genda in Drama CD.

Jun Fukuyama will voicing Kiefer (DQ7)?

Original protagonists have voiced by generic actor, not voice actor.
And Alena is voiced by talent.
I hope Shun Oguri got one of role in this game.