Portrait of the MSN-00100 Hyaku Shiki from "Gundam" anime "Mobile Suit Z Gundam" (a.k.a. Mobile Suit Zeta Gundam) and "Mobile Suit Gundam ZZ" (a.k.a. Mobile Suit Gundam Double-Zeta).
This mobile suit is partly famous not only for its similarities with the ORB-01 Akatsuki from "Mobile Suit Gundam SEED Destiny", but also for the fact that it was first piloted by one of "Gundam"'s most popular male characters: Char Aznable (a.k.a. Quattro Bajeena).
I did this drawing while viewing the front cover of an "HG Universal Century" model kit box, and it took me nearly two hours to approx. to complete the task.
For all fans of "Gundam" (including those who like classic "Gundam", which is setted in Universal Century) and classic mecha anime to enjoy!