A sapient who makes excessive and often unbalanced use of augments, including sucyborgism and transcyborgism, in order to achieve maximum proficiency in specific areas. (there are also apparently equivalents among transapients, but they are much less well known)
Not infrequently Powermodders use technology that is illegal in the Sephirotic regions, or push safe tech beyond its recommended design limits. Because they don't have sufficient grounding and understanding in the bio-, nano-, info- and psychoengineering technologies they employ, Powermodders frequently suffer from mental and physical dysfunction, soobooism, involuntary overwrites, nanonic and neuronal burnout, and more. This hasn't stopped powermodding being incredibly popular in some wildhu and non-sephirotic feral zones. In the Sephirotic regions however, powermodding is never engaged in in anything other than experimental dysfunctions and other quirks, and always with careful full backup beforehand. True powermodders see this as dilettantism, and many (although not all) resent advice or guidance from transapients or expert systems which recommend the dangers and self-limitations of powermodding.
Powermodders tend to avoid the angelnetted nanotopias, because most angelnets will require them to deactivate their mods (or do it for them if they object) for the period of their stay. Some powermodders are also hu supremacists, and vice versa, but it is equally common for powermodders to reject hu supremacist, and any other anthropist, ideologies and meme-systems, seeing these as enforcing limitations on how far they can go with their augmentations and enhancements.
Among unaugmented or optimodded sapients, powermodders can be formidable characters, sometimes packing as much power as SI:1 transapients, although never with the precision, understanding, subtly, or just general ability and insight to use this power correctly, or best a transapient on its own terms. Like Transavants, they exist in a sort of middle region between singularity levels.
Powermodders are frequently found as adventurers and godchasers throughout the civilized galaxy and beyond, as mercenaries in less regulated middle and high tech worlds and polities in the hinteregions and outer volumes, and as extreme sportists and hobbyists everywhere.