A Dyna-Host is a baseline who is host to a Dynamorph. The situation is somewhat similar to the mutant Avatar Trait, but there are very significant differences, which are not well-defined at present.
The bonding grants the host super-powers. Those powers are apparently not magical in nature, as Avatar powers are, since Dynamorphs aren't magical themselves and "do not mix well with magic".
Teenage hosts exist, but are rare. Dynamorphs seem to prefer bonding with mature and dynamic host, who will actively use their powers (usually as superheroes or supervillains). Insane hosts tend to lose control of their Dynamorphs.
It is possible to remove a Dynamorph from it's host. It is done to dangerous criminals or younger hosts ("for their own protection"). This is highly controversial, but since being a Dyna-Host isn't a natural condition, it is argued that they do not have any right to keep a Dynamorph, and it is thus legal for the Government to take it away. It is unknown if it is possible to do the reverse and create a bond without the Dynamorph being the initiator.
Dynamorph bonding seems to be a recent phenomenon. The first confirmed Dyna-Host was Bristol Marvel, in Great Britain, in 1934.
Most of this information comes from the second chapter of Silver Linings.[1]
Chopper, of the Felonious Four, is suspected to be a Dyna-host.[2]
Kristin Darken on April 8, 2017 explained:
- Dyna-morphs... are generally a non-spirit version of spirits for non-avatars. Hosting a Dyna-morph can generally have much the same result for a regular human as hosting a spirit can for Avatars.[3]