The default world state assumes a female Dalish Elf warrior Warden who died killing the Archdemon in Origins and a male mage Hawke who sided with the mages in Dragon Age II. There is also a default world state, for players who did not play the previous games or do not wish to bother with the Keep. This adds replay value as it allows to start a new playthrough with a completely different world state. Approximately 300 different choices can be made in the Keep. Dragon Age: Inquisition has replaced importing old saves with the Dragon Age Keep, a website where players are able to determine decisions made in the previous games as they see fit.If you import just the Origins save without Awakening flags, those will be preset for you.
See also No Canon for the Wicked, where the hero path is exclusively canon in a franchise with a morality system. Merging the Branches is a specific form of this where events from several mutually exclusive story branches are declared canon, rather than a single specific branch. See also Canon Name, where a character who didn't have a given name at all in the first game, is given one in the next.
If the branches were selected immediately from character selection, you're using Schrödinger's Player Character. When the next work is also a video game instead of an extended universe entry, this can sometimes be averted with Old Save Bonus or Schrödinger's Question. Contrast with Third-Option Adaptation, which ignores all the various plotlines and picks an outside choice. Related to Story Branch Favoritism: the plot branch that receives the most focus is more likely to be chosen as canon in a sequel. In short, cutting off the branches is when one of the multiple possible endings in a game is considered the canon one in a future adaptation.