Founders/Changelings:are very different. They are basically liquid. They can take any solid shape, organic or inorganic. They can be any person. One way to test if their humanoid or not is to cut them and let the blood drop onto something. If it remains blood then they are humanoid. They are the rulers of the Dominion. They feel they are superior to everyone else. They don't get involved in anything themselves. They use their genetically engineered slaves to do their dirty work. They can get into other changelings minds by turning liquid and joining with them. They cannot stay in solid form for too long. They need a regeneration period.

Jem'Hadar:are genetically engineered soldiers. They are dependent on a substance known as white. The Founders are the only ones that know how to provide it. They don't eat or sleep. By genetics, they are loyal to the founders and consider them gods. Jem'Hadars most prominent physical characteristics are their scaly skin and horns on the bottom and the top of their face.

Vorta:are genetically engineered diplomats. They too are loyal to the founders and consider them gods. When one dies it is cloned. They command the Jem'Hadar. They also speak for the founders. They have excellent hearing, but not so good sight. Vorta's most prominent physical feature are the ridges on the sides of their heads and ears.