This series was adapted from the novel with the same title, which was started 1986 and still ongoing. There exists an OVA before this in early 2000 I think. Some people says that the novel is kinda.. BL-ish but Arakawa Hiromu's newer manga (and now anime) adaptation focuses more on the conflicts of the countries, betrayal and war. There is indeed a lack of humor but just like in the case of Romance of the Three Kingdom, it wanted to stay true to the storyline and I can put my faith in Arakawa's expertise for this kind of story. The animation is great and smooth, neat plotline and the level of seriousness are toned down for larger viewer demographics. If your kind of genre including war, political conflicts and on the serious side, do give this one a try. It does not deal with psychological conflicts as much, so it is not as heavy as Psycho Pass.

P/S: Some people may find this anime to be quite similar with Akatsuki no Yona, but do remember that this was adapted from a 1986 novel, while Akatsuki's manga was serialized in 2006/7. Although Akatsuki's anime came out first, it does not mean Arslan Senki anime copied Akatsuki no Yona. And it does not mean Akatsuki no Yona manga copied The Heroic Legend of Arslan's original novel, it is just that this type of story is very common so it is not weird to see similar story. (show less)