Cleon
Legend
Well, here's something rough:
Oceanus Jaunt (Su): A delphon moves freely through Oceanus and the planes it touches. A delphon can shift from Oceanus to any adjoining plane as part of any move action, and shift back again as a free action; this ability functions otherwise as the ethereal jaunt spell (caster level 15). In addition, a delphon can teleport within Oceanus, as dimension door (caster level 15th), as a swift action. The ability affects only the delphon, which never appears within a solid object and can act immediately after teleporting.
The original delphon can teleport away from an attack 25% of the time, so I'd give it blink as well.
Apart from that the basics looks fine, although I'd like tidy up the language a bit:
Revising...
Oceanus Jaunt (Su): A delphon moves freely through Oceanus and the planes it touches. A delphon can shift from Oceanus to any adjoining plane as part of any move action, and shift back again as a free action; this ability is otherwise identical with the ethereal jaunt spell (caster level 15). In addition, a delphon can teleport at will between points within Oceanus, allowing it to use dimension door as a swift action (caster level 15th) and blink as the spell (caster level 15th, it can evoke or end the blink effect as a free action). Oceanus jaunt affects only the delphon, which never appears within a solid object and can act immediately after jaunting.