Ok looks like you need some clues. ^^
Here is another picture of the man.
The hint are his Body(muscles not clothes) and the Weapon he is using.
And another hint.
This is the Female main character of the Anime i'm searching for and she is a Mermaid.
I think this should help a bit. ^^
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I think it's to difficult if you don't know anything about the Anime so I dropped the first question and I give you the answer as additional clue.
The name of the serie is Seto no Hanayome.