This Turtum was called into being when the Founder created Petaria, destined to be the guardian for the element of Water. He set up home on the Iceberg Archipelago. Eventually the Dark Guardian had him imprisoned in ice, and the Triffin took over his home. Thankfully, Fluffy freed him.
At last! Warmth! I feared I would be frozen forever.
Such valour must be recognised and rewarded. Please accept these trinkets I've had lying around.
While it's true the Triffin imprisoned me, he is far too dull to be the source of this evil.
Seek out the Light Guardian. As the brightest of us, she may have better insight regarding this dastardly plot.
To enter her lair you will need this Prismatic Diamond.
I can fend for myself now. Go and find the Light Guardian on Shadow Island!
During the final fight, the guardian uses the word 'Aquin'. It is unclear if that is the guardian's name, or just part of a spell.