Digital Enhancement
When a Contract is successfully made with a Digimon, it will give a Tamer two things. One is a small barrier to protect him or her from strong attacks. The barrier isn't all powerful and can shatter with enough force or action. The other is called the Digital Enhancement, or simply DE. The DE is an upgrade to the human to allow him/herself defense against other humans and Digimon. An enhancement is never really flashy, with only tell tale signs when it becomes active. This is because secrecy is important, and big flashy displays of power attract unwanted attention. Enhancements include small elemental manipulation, bodily enhancement, mental enhancement, stuff like that.
Acceptable ideas are higher body strength, telekinesis, telepathy, short range teleportation, super speed, small healing, sudden skill in weaponry, and transforming. Unacceptable ideas include lasers, transformation that also copies powers, big shows of energy, anything Dragonball Z-esque, Gurren-Lagann-ish, or simply over the bloody top. Remember, subtlety is the key here, being a Tamer and having a Digimon is supposed to be a SECRET.
Though subtlety is still key, some flashiness can be afforded with higher levels. DE's have three levels: Initial, Advance, and Unrestricted.
Digital Enhancements, also known as Enhancements or simply DEs are a form of psychic power unlocked by the formation of a Contract with a Digimon. It could be termed "an upgrade to the human"; it's also a power that operates on the Wish/the inner desires of the human forming the Contract. For example, someone who desired to prove their genius to the world might gain an Enhancement that allows them to increase their thinking speed or brain capacity; someone who desired to express pent-up frustrations might gain something like pyrokinesis.
The capability, it must be noted, is native to the Tamer's brain--the Digivice and the Contract it carries act as something akin to an "ignition key", activating the "engine" of the Tamer's psychic capabilities. A Tamer's brain will register as different from a normal human's to close examination--the area of the cortex that controls the Digital Enhancement is larger and more pronounced than the dormant area in a normal human's. There may also be some slight biological changes to cope with the unique power granted.