Pull Against the Tide
From Shousetsu Bang*Bang Wiki
Pull Against the Tide is a story written and illustrated by staringatsuns. It ran in Issue 58 at http://s2b2.livejournal.com/325809.html, and will be mirrored at http://www.shousetsubangbang.com/mirror/.
Summary
From fairyninjas.wordpress.com: "A merman on a mission changes his means and goals for a while, and then meets an old frienemy, and then changes his goals a bit more, until everything is different, and there’s a happy ending for everyone we care about."