Kevin Tremain was a mutant captured and studied by the Mandarin. On a secret mission, the Six Pack attacked the secret base Tremain was held in. Tremain was mortally injured; Cable tried to save his life, first by using his telekinesis to keep Tremain's body together, and finally by giving him a blood transfusion. Although it seems he survived this trauma, Cable seemed to think Tremain had later died.
Years later, Tremain resurfaced as Post, the lowest of Onslaught's emissaries. Onslaught forced Gateway to teleport Cyclops, Storm, Iceman, and Wolverine to where Post could "test" them. The four managed to defeat Post and were transported back to the Mansion. Later, Post attacked Cable, who instantly recognized his identity as Tremain. Post defeated Cable and left him for the Hulk to finish off. Post was later charged with ensuring the Sentinels would launch, he battled X-Factor with them and succeeded protecting the Sentinels. He and his master Onslaught were eventually defeated by the heroes.
Darwin encourages a component- or object-based approach to program structuring in which the unit of structure (the component) hides its behaviour behind a well-defined interface. Programs are constructed by creating instances of component types and binding their interfaces together. Darwin considers such compositions also to be types and hence encourages hierarchical composition. The general form of a Darwin program is therefore the tree in which the root and all intermediate nodes are composite components; the leaves are primitive components encapsulating behavioural as opposed to structural aspects.
The game consisted of a program called the umpire and a designated section of the computer's memory known as the arena, into which two or more small programs, written by the players, were loaded. The programs were written in 7090 machine code, and could call a number of functions provided by the umpire in order to probe other locations within the arena, kill opposing programs, and claim vacant memory for copies of themselves.
The game ended after a set amount of time, or when copies of only one program remained alive. The player who wrote the last surviving program was declared winner.