There are a lot of reference points, not none. Our galaxy rotates about a center forming a plane, more or less, and objects are stated to be above or below the galactic plane. The sun rotates and has an equator. Extrapolating that equatorial plane produces the solar plane, and planets move above and below it all the time. Similarly, the earth's equator can be compared to the solar plane. The equator (and thus the poles) is tilted with respect to the solar plane.
There is also a time point of reference, from the big bang to the creation of our solar system and its evolution to its present state.
The coorect way to describe the earth's tilt is not "off axis" but "off the vertical" from the solar plane. The earth's axis is the earth's axis. It's not "off" its own axis.