Mermaid Forest is a philosophical anime which primarily explores the curse of immortality. But despite its philosophical nature, don't be fooled into thinking that this is a relaxed anime; there is plenty of action, suspense and even gore in the stories!
There is a little romance in this anime and there is virtually no "fan service" or comedy moments (which depending on what you're looking for in anime, could be either a good thing or a bad thing).
Characters;
Yuta: A compassionate and intelligent man with a strong sense of justice, he is also a lonely man who carries numerous heavy emotional burdens. He was cursed with immortality after accidentally consuming mermaid flesh and ever since that day he has traveled the length and breadth of country looking for a way to undo the curse.
Mana: A beautiful 15 year old girl who was also cursed with immortality after unwittingly eating mermaid flesh that had been deliberately given to her to eat. She was held captive all her life but was saved by Yuta. Mana is quite serious girl but after having spent so much of her life in virtual isolation in captivity, has very little experience nor knowledge of the modern world (but while innocent she is also quick witted and a fast learner).
The artistic style of this anime makes it look very dated. And to be fair, being released over 12 years ago, it is an old anime by today's standards. But please don't let this put you off!
This anime is a quality work with original stories and interesting characters. Most of the stories take 1-2 episodes to complete however they are all relevant and all link up together to culminate in a more significant ending. This anime is also steeped in a fair bit of Japanese folklore and history. So if you're looking for an anime with interesting story lines which explore philosophy, morality and folklore etc, then Mermaid Forest is a perfect anime for you!