If you're looking for manga similar to Siren, you might like these titles.
Denzel Westwood is a young, talented magician without a care in the world, until one day his eyes suddenly begin to turn amber, prompting a series of events which will lead him to discover the truth of the world in which he lives and the mysterious Abyss which surrounds it. This is the story of a boy filled with light.
The secret behind the goblin's wife that appears once every one thousand years....
Jinho and Chundo are two best friends wasting their summer days away. But when they find a lottery ticket on the street by chance, they're thrown into a mysterious treasure hunt with two strange girls they don't fully understand.