the watcher in the water

[The Saucepan Man]

He even goes straight for the most important member of the group.

Whatever the Kraken's motive, it is clear from the manner of its attack that it is after Frodo. This might be because it is a Servant of Sauron, or it might be simply because, as an "evil" creature, it senses the evil power of the Ring.

The latter seems more likely to me, since it is unlikely that, before snacking on Frodo, the Kraken would have removed the Ring and set it on one side to be collected by his friendly neighbourhood Nazgul later. The Ring would have ended up at the bottom of the lake and quite possibly not been "found" until a good many years later, thus delaying Sauron's planned takeover of ME.

By the way, I don't think that there is any evidence that Melkor/Morgoth created Dragons is there? They do not all serve the Dark Lords (Smaug, for example, who was simply out for himself).