Promotion also upgrades one's skill. For example, Adenium's single-target no-drain skill with x2.4 damage (30% proc rate at skill level 5) will be upgraded to an HP drain skill with x4.3 damage (36% proc rate at skill level 5) after Promotion. None of the Wiki admins has yet to work on a code that will auto-generate such data though; hence the lack of data on character pages.
Nevertheless, HydroKirby made Comprehensive Knight List that reflects an eligible character's skill, stats, and abilities as if she has been promoted.